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MAUI Blazor 如何通过url使用本地文件 - Yu-Core
来源：cnblogs　　作者：Yu-Core　　时间：2023/11/29 16:17:43　　对本文有异议

前言

上一篇文章 MAUI Blazor 显示本地图片的新思路 中, 提出了通过webview拦截，从而在前端中显示本地图片的思路。不过当时还不完善，随后也发现了很多问题。比如，

  1. 不同平台上的url不统一。这对于需要存储图片路径并且多端互通的需求来说，并不友好。至少 FileSystem.AppDataDirectory 和 FileSystem.CacheDirectory 下的文件生成的url应该统一。
  2. 音频文件和视频文件无法使用。理论上可以用于各种文件，但是音频和视频不能播放，应该是需要相应的处理
  3. Windows上有限制。大于9~10M的图片不显示
  4. iOS/ Mac有跨域问题。尤其是调用用于截图的js库，图片会由于跨域不出现在截图中

所以，在这篇文章中，对这个思路进行完善，使之成为一个可行的方案。

例如 <img src='appdata/Image/image1.jpg' > 会显示 FileSystem.AppDataDirectory 文件夹下的 Image 文件夹下的 image1.jpg 这个图片
<video src='cache/Video/video1.mp4' controls > 会播放 FileSystem.CacheDirectory 文件夹下的 Video 文件夹下的 video1.mp4 这个视频
对于其他路径的文件来说，url设为 file/ 加上转义后的完整路径

正文

准备工作

新建一个MAUI Blazor项目

参考 配置基于文件名的多目标 ，更改项目文件（以.csproj结尾的文件），添加以下代码

  1. <!-- Android -->
  2. <ItemGroup Condition="$(TargetFramework.StartsWith('net8.0-android')) != true">
  3.   <Compile Remove="**\**\*.Android.cs" />
  4.   <None Include="**\**\*.Android.cs" Exclude="$(DefaultItemExcludes);$(DefaultExcludesInProjectFolder)" />
  5. </ItemGroup>
  7. <!-- Both iOS and Mac Catalyst -->
  8. <ItemGroup Condition="$(TargetFramework.StartsWith('net8.0-ios')) != true AND $(TargetFramework.StartsWith('net8.0-maccatalyst')) != true">
  9.   <Compile Remove="**\**\*.MaciOS.cs" />
  10.   <None Include="**\**\*.MaciOS.cs" Exclude="$(DefaultItemExcludes);$(DefaultExcludesInProjectFolder)" />
  11. </ItemGroup>
  13. <!-- iOS -->
  14. <ItemGroup Condition="$(TargetFramework.StartsWith('net8.0-ios')) != true">
  15.   <Compile Remove="**\**\*.iOS.cs" />
  16.   <None Include="**\**\*.iOS.cs" Exclude="$(DefaultItemExcludes);$(DefaultExcludesInProjectFolder)" />
  17. </ItemGroup>
  19. <!-- Mac Catalyst -->
  20. <ItemGroup Condition="$(TargetFramework.StartsWith('net8.0-maccatalyst')) != true">
  21.   <Compile Remove="**\**\*.MacCatalyst.cs" />
  22.   <None Include="**\**\*.MacCatalyst.cs" Exclude="$(DefaultItemExcludes);$(DefaultExcludesInProjectFolder)" />
  23. </ItemGroup>
  25. <!-- Windows -->
  26. <ItemGroup Condition="$(TargetFramework.Contains('-windows')) != true">
  27.   <Compile Remove="**\*.Windows.cs" />
  28.   <None Include="**\*.Windows.cs" Exclude="$(DefaultItemExcludes);$(DefaultExcludesInProjectFolder)" />
  29. </ItemGroup>

添加一个处理ContentType的静态类

用来获取文件的ContentType
没找到什么太好的方法，偶然看到Maui的源码中的一段，还不错，不过是internal修饰的，就直接抄来了
新建Utilities/MimeType文件夹，在里面添加 StaticContentProvider.cs
代码如下：

  1. #nullable disable
  2. // Copyright (c) .NET Foundation. All rights reserved.
  3. // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
  5. using System.Diagnostics.CodeAnalysis;
  7. namespace MauiBlazorLocalMediaFile.Utilities
  8. {
  9.     internal partial class StaticContentProvider
  10. 	{
  11. 		private static readonly FileExtensionContentTypeProvider ContentTypeProvider = new();
  13. 		internal static string GetResponseContentTypeOrDefault(string path)
  14. 			=> ContentTypeProvider.TryGetContentType(path, out var matchedContentType)
  15. 			? matchedContentType
  16. 			: "application/octet-stream";
  18. 		internal static IDictionary<string, string> GetResponseHeaders(string contentType)
  19. 			=> new Dictionary<string, string>(StringComparer.Ordinal)
  20. 			{
  21. 				{ "Content-Type", contentType },
  22. 				{ "Cache-Control", "no-cache, max-age=0, must-revalidate, no-store" },
  23. 			};
  25. 		internal class FileExtensionContentTypeProvider
  26. 		{
  27. 			// Notes:
  28. 			// - This table was initially copied from IIS and has many legacy entries we will maintain for backwards compatibility.
  29. 			// - We only plan to add new entries where we expect them to be applicable to a majority of developers such as being
  30. 			// used in the project templates.
  31. 			#region Extension mapping table
  32. 			/// <summary>
  33. 			/// Creates a new provider with a set of default mappings.
  34. 			/// </summary>
  35. 			public FileExtensionContentTypeProvider()
  36. 				: this(new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase)
  37. 				{
  38. 				{ ".323", "text/h323" },
  39. 				{ ".3g2", "video/3gpp2" },
  40. 				{ ".3gp2", "video/3gpp2" },
  41. 				{ ".3gp", "video/3gpp" },
  42. 				{ ".3gpp", "video/3gpp" },
  43. 				{ ".aac", "audio/aac" },
  44. 				{ ".aaf", "application/octet-stream" },
  45. 				{ ".aca", "application/octet-stream" },
  46. 				{ ".accdb", "application/msaccess" },
  47. 				{ ".accde", "application/msaccess" },
  48. 				{ ".accdt", "application/msaccess" },
  49. 				{ ".acx", "application/internet-property-stream" },
  50. 				{ ".adt", "audio/vnd.dlna.adts" },
  51. 				{ ".adts", "audio/vnd.dlna.adts" },
  52. 				{ ".afm", "application/octet-stream" },
  53. 				{ ".ai", "application/postscript" },
  54. 				{ ".aif", "audio/x-aiff" },
  55. 				{ ".aifc", "audio/aiff" },
  56. 				{ ".aiff", "audio/aiff" },
  57. 				{ ".appcache", "text/cache-manifest" },
  58. 				{ ".application", "application/x-ms-application" },
  59. 				{ ".art", "image/x-jg" },
  60. 				{ ".asd", "application/octet-stream" },
  61. 				{ ".asf", "video/x-ms-asf" },
  62. 				{ ".asi", "application/octet-stream" },
  63. 				{ ".asm", "text/plain" },
  64. 				{ ".asr", "video/x-ms-asf" },
  65. 				{ ".asx", "video/x-ms-asf" },
  66. 				{ ".atom", "application/atom+xml" },
  67. 				{ ".au", "audio/basic" },
  68. 				{ ".avi", "video/x-msvideo" },
  69. 				{ ".axs", "application/olescript" },
  70. 				{ ".bas", "text/plain" },
  71. 				{ ".bcpio", "application/x-bcpio" },
  72. 				{ ".bin", "application/octet-stream" },
  73. 				{ ".bmp", "image/bmp" },
  74. 				{ ".c", "text/plain" },
  75. 				{ ".cab", "application/vnd.ms-cab-compressed" },
  76. 				{ ".calx", "application/vnd.ms-office.calx" },
  77. 				{ ".cat", "application/vnd.ms-pki.seccat" },
  78. 				{ ".cdf", "application/x-cdf" },
  79. 				{ ".chm", "application/octet-stream" },
  80. 				{ ".class", "application/x-java-applet" },
  81. 				{ ".clp", "application/x-msclip" },
  82. 				{ ".cmx", "image/x-cmx" },
  83. 				{ ".cnf", "text/plain" },
  84. 				{ ".cod", "image/cis-cod" },
  85. 				{ ".cpio", "application/x-cpio" },
  86. 				{ ".cpp", "text/plain" },
  87. 				{ ".crd", "application/x-mscardfile" },
  88. 				{ ".crl", "application/pkix-crl" },
  89. 				{ ".crt", "application/x-x509-ca-cert" },
  90. 				{ ".csh", "application/x-csh" },
  91. 				{ ".css", "text/css" },
  92. 				{ ".csv", "text/csv" }, // https://tools.ietf.org/html/rfc7111#section-5.1
  93.                 { ".cur", "application/octet-stream" },
  94. 				{ ".dcr", "application/x-director" },
  95. 				{ ".deploy", "application/octet-stream" },
  96. 				{ ".der", "application/x-x509-ca-cert" },
  97. 				{ ".dib", "image/bmp" },
  98. 				{ ".dir", "application/x-director" },
  99. 				{ ".disco", "text/xml" },
  100. 				{ ".dlm", "text/dlm" },
  101. 				{ ".doc", "application/msword" },
  102. 				{ ".docm", "application/vnd.ms-word.document.macroEnabled.12" },
  103. 				{ ".docx", "application/vnd.openxmlformats-officedocument.wordprocessingml.document" },
  104. 				{ ".dot", "application/msword" },
  105. 				{ ".dotm", "application/vnd.ms-word.template.macroEnabled.12" },
  106. 				{ ".dotx", "application/vnd.openxmlformats-officedocument.wordprocessingml.template" },
  107. 				{ ".dsp", "application/octet-stream" },
  108. 				{ ".dtd", "text/xml" },
  109. 				{ ".dvi", "application/x-dvi" },
  110. 				{ ".dvr-ms", "video/x-ms-dvr" },
  111. 				{ ".dwf", "drawing/x-dwf" },
  112. 				{ ".dwp", "application/octet-stream" },
  113. 				{ ".dxr", "application/x-director" },
  114. 				{ ".eml", "message/rfc822" },
  115. 				{ ".emz", "application/octet-stream" },
  116. 				{ ".eot", "application/vnd.ms-fontobject" },
  117. 				{ ".eps", "application/postscript" },
  118. 				{ ".etx", "text/x-setext" },
  119. 				{ ".evy", "application/envoy" },
  120. 				{ ".exe", "application/vnd.microsoft.portable-executable" }, // https://www.iana.org/assignments/media-types/application/vnd.microsoft.portable-executable
  121.                 { ".fdf", "application/vnd.fdf" },
  122. 				{ ".fif", "application/fractals" },
  123. 				{ ".fla", "application/octet-stream" },
  124. 				{ ".flr", "x-world/x-vrml" },
  125. 				{ ".flv", "video/x-flv" },
  126. 				{ ".gif", "image/gif" },
  127. 				{ ".gtar", "application/x-gtar" },
  128. 				{ ".gz", "application/x-gzip" },
  129. 				{ ".h", "text/plain" },
  130. 				{ ".hdf", "application/x-hdf" },
  131. 				{ ".hdml", "text/x-hdml" },
  132. 				{ ".hhc", "application/x-oleobject" },
  133. 				{ ".hhk", "application/octet-stream" },
  134. 				{ ".hhp", "application/octet-stream" },
  135. 				{ ".hlp", "application/winhlp" },
  136. 				{ ".hqx", "application/mac-binhex40" },
  137. 				{ ".hta", "application/hta" },
  138. 				{ ".htc", "text/x-component" },
  139. 				{ ".htm", "text/html" },
  140. 				{ ".html", "text/html" },
  141. 				{ ".htt", "text/webviewhtml" },
  142. 				{ ".hxt", "text/html" },
  143. 				{ ".ical", "text/calendar" },
  144. 				{ ".icalendar", "text/calendar" },
  145. 				{ ".ico", "image/x-icon" },
  146. 				{ ".ics", "text/calendar" },
  147. 				{ ".ief", "image/ief" },
  148. 				{ ".ifb", "text/calendar" },
  149. 				{ ".iii", "application/x-iphone" },
  150. 				{ ".inf", "application/octet-stream" },
  151. 				{ ".ins", "application/x-internet-signup" },
  152. 				{ ".isp", "application/x-internet-signup" },
  153. 				{ ".IVF", "video/x-ivf" },
  154. 				{ ".jar", "application/java-archive" },
  155. 				{ ".java", "application/octet-stream" },
  156. 				{ ".jck", "application/liquidmotion" },
  157. 				{ ".jcz", "application/liquidmotion" },
  158. 				{ ".jfif", "image/pjpeg" },
  159. 				{ ".jpb", "application/octet-stream" },
  160. 				{ ".jpe", "image/jpeg" },
  161. 				{ ".jpeg", "image/jpeg" },
  162. 				{ ".jpg", "image/jpeg" },
  163. 				{ ".js", "application/javascript" },
  164. 				{ ".json", "application/json" },
  165. 				{ ".jsx", "text/jscript" },
  166. 				{ ".latex", "application/x-latex" },
  167. 				{ ".lit", "application/x-ms-reader" },
  168. 				{ ".lpk", "application/octet-stream" },
  169. 				{ ".lsf", "video/x-la-asf" },
  170. 				{ ".lsx", "video/x-la-asf" },
  171. 				{ ".lzh", "application/octet-stream" },
  172. 				{ ".m13", "application/x-msmediaview" },
  173. 				{ ".m14", "application/x-msmediaview" },
  174. 				{ ".m1v", "video/mpeg" },
  175. 				{ ".m2ts", "video/vnd.dlna.mpeg-tts" },
  176. 				{ ".m3u", "audio/x-mpegurl" },
  177. 				{ ".m4a", "audio/mp4" },
  178. 				{ ".m4v", "video/mp4" },
  179. 				{ ".man", "application/x-troff-man" },
  180. 				{ ".manifest", "application/x-ms-manifest" },
  181. 				{ ".map", "text/plain" },
  182. 				{ ".markdown", "text/markdown" },
  183. 				{ ".md", "text/markdown" },
  184. 				{ ".mdb", "application/x-msaccess" },
  185. 				{ ".mdp", "application/octet-stream" },
  186. 				{ ".me", "application/x-troff-me" },
  187. 				{ ".mht", "message/rfc822" },
  188. 				{ ".mhtml", "message/rfc822" },
  189. 				{ ".mid", "audio/mid" },
  190. 				{ ".midi", "audio/mid" },
  191. 				{ ".mix", "application/octet-stream" },
  192. 				{ ".mmf", "application/x-smaf" },
  193. 				{ ".mno", "text/xml" },
  194. 				{ ".mny", "application/x-msmoney" },
  195. 				{ ".mov", "video/quicktime" },
  196. 				{ ".movie", "video/x-sgi-movie" },
  197. 				{ ".mp2", "video/mpeg" },
  198. 				{ ".mp3", "audio/mpeg" },
  199. 				{ ".mp4", "video/mp4" },
  200. 				{ ".mp4v", "video/mp4" },
  201. 				{ ".mpa", "video/mpeg" },
  202. 				{ ".mpe", "video/mpeg" },
  203. 				{ ".mpeg", "video/mpeg" },
  204. 				{ ".mpg", "video/mpeg" },
  205. 				{ ".mpp", "application/vnd.ms-project" },
  206. 				{ ".mpv2", "video/mpeg" },
  207. 				{ ".ms", "application/x-troff-ms" },
  208. 				{ ".msi", "application/octet-stream" },
  209. 				{ ".mso", "application/octet-stream" },
  210. 				{ ".mvb", "application/x-msmediaview" },
  211. 				{ ".mvc", "application/x-miva-compiled" },
  212. 				{ ".nc", "application/x-netcdf" },
  213. 				{ ".nsc", "video/x-ms-asf" },
  214. 				{ ".nws", "message/rfc822" },
  215. 				{ ".ocx", "application/octet-stream" },
  216. 				{ ".oda", "application/oda" },
  217. 				{ ".odc", "text/x-ms-odc" },
  218. 				{ ".ods", "application/oleobject" },
  219. 				{ ".oga", "audio/ogg" },
  220. 				{ ".ogg", "video/ogg" },
  221. 				{ ".ogv", "video/ogg" },
  222. 				{ ".ogx", "application/ogg" },
  223. 				{ ".one", "application/onenote" },
  224. 				{ ".onea", "application/onenote" },
  225. 				{ ".onetoc", "application/onenote" },
  226. 				{ ".onetoc2", "application/onenote" },
  227. 				{ ".onetmp", "application/onenote" },
  228. 				{ ".onepkg", "application/onenote" },
  229. 				{ ".osdx", "application/opensearchdescription+xml" },
  230. 				{ ".otf", "font/otf" },
  231. 				{ ".p10", "application/pkcs10" },
  232. 				{ ".p12", "application/x-pkcs12" },
  233. 				{ ".p7b", "application/x-pkcs7-certificates" },
  234. 				{ ".p7c", "application/pkcs7-mime" },
  235. 				{ ".p7m", "application/pkcs7-mime" },
  236. 				{ ".p7r", "application/x-pkcs7-certreqresp" },
  237. 				{ ".p7s", "application/pkcs7-signature" },
  238. 				{ ".pbm", "image/x-portable-bitmap" },
  239. 				{ ".pcx", "application/octet-stream" },
  240. 				{ ".pcz", "application/octet-stream" },
  241. 				{ ".pdf", "application/pdf" },
  242. 				{ ".pfb", "application/octet-stream" },
  243. 				{ ".pfm", "application/octet-stream" },
  244. 				{ ".pfx", "application/x-pkcs12" },
  245. 				{ ".pgm", "image/x-portable-graymap" },
  246. 				{ ".pko", "application/vnd.ms-pki.pko" },
  247. 				{ ".pma", "application/x-perfmon" },
  248. 				{ ".pmc", "application/x-perfmon" },
  249. 				{ ".pml", "application/x-perfmon" },
  250. 				{ ".pmr", "application/x-perfmon" },
  251. 				{ ".pmw", "application/x-perfmon" },
  252. 				{ ".png", "image/png" },
  253. 				{ ".pnm", "image/x-portable-anymap" },
  254. 				{ ".pnz", "image/png" },
  255. 				{ ".pot", "application/vnd.ms-powerpoint" },
  256. 				{ ".potm", "application/vnd.ms-powerpoint.template.macroEnabled.12" },
  257. 				{ ".potx", "application/vnd.openxmlformats-officedocument.presentationml.template" },
  258. 				{ ".ppam", "application/vnd.ms-powerpoint.addin.macroEnabled.12" },
  259. 				{ ".ppm", "image/x-portable-pixmap" },
  260. 				{ ".pps", "application/vnd.ms-powerpoint" },
  261. 				{ ".ppsm", "application/vnd.ms-powerpoint.slideshow.macroEnabled.12" },
  262. 				{ ".ppsx", "application/vnd.openxmlformats-officedocument.presentationml.slideshow" },
  263. 				{ ".ppt", "application/vnd.ms-powerpoint" },
  264. 				{ ".pptm", "application/vnd.ms-powerpoint.presentation.macroEnabled.12" },
  265. 				{ ".pptx", "application/vnd.openxmlformats-officedocument.presentationml.presentation" },
  266. 				{ ".prf", "application/pics-rules" },
  267. 				{ ".prm", "application/octet-stream" },
  268. 				{ ".prx", "application/octet-stream" },
  269. 				{ ".ps", "application/postscript" },
  270. 				{ ".psd", "application/octet-stream" },
  271. 				{ ".psm", "application/octet-stream" },
  272. 				{ ".psp", "application/octet-stream" },
  273. 				{ ".pub", "application/x-mspublisher" },
  274. 				{ ".qt", "video/quicktime" },
  275. 				{ ".qtl", "application/x-quicktimeplayer" },
  276. 				{ ".qxd", "application/octet-stream" },
  277. 				{ ".ra", "audio/x-pn-realaudio" },
  278. 				{ ".ram", "audio/x-pn-realaudio" },
  279. 				{ ".rar", "application/octet-stream" },
  280. 				{ ".ras", "image/x-cmu-raster" },
  281. 				{ ".rf", "image/vnd.rn-realflash" },
  282. 				{ ".rgb", "image/x-rgb" },
  283. 				{ ".rm", "application/vnd.rn-realmedia" },
  284. 				{ ".rmi", "audio/mid" },
  285. 				{ ".roff", "application/x-troff" },
  286. 				{ ".rpm", "audio/x-pn-realaudio-plugin" },
  287. 				{ ".rtf", "application/rtf" },
  288. 				{ ".rtx", "text/richtext" },
  289. 				{ ".scd", "application/x-msschedule" },
  290. 				{ ".sct", "text/scriptlet" },
  291. 				{ ".sea", "application/octet-stream" },
  292. 				{ ".setpay", "application/set-payment-initiation" },
  293. 				{ ".setreg", "application/set-registration-initiation" },
  294. 				{ ".sgml", "text/sgml" },
  295. 				{ ".sh", "application/x-sh" },
  296. 				{ ".shar", "application/x-shar" },
  297. 				{ ".sit", "application/x-stuffit" },
  298. 				{ ".sldm", "application/vnd.ms-powerpoint.slide.macroEnabled.12" },
  299. 				{ ".sldx", "application/vnd.openxmlformats-officedocument.presentationml.slide" },
  300. 				{ ".smd", "audio/x-smd" },
  301. 				{ ".smi", "application/octet-stream" },
  302. 				{ ".smx", "audio/x-smd" },
  303. 				{ ".smz", "audio/x-smd" },
  304. 				{ ".snd", "audio/basic" },
  305. 				{ ".snp", "application/octet-stream" },
  306. 				{ ".spc", "application/x-pkcs7-certificates" },
  307. 				{ ".spl", "application/futuresplash" },
  308. 				{ ".spx", "audio/ogg" },
  309. 				{ ".src", "application/x-wais-source" },
  310. 				{ ".ssm", "application/streamingmedia" },
  311. 				{ ".sst", "application/vnd.ms-pki.certstore" },
  312. 				{ ".stl", "application/vnd.ms-pki.stl" },
  313. 				{ ".sv4cpio", "application/x-sv4cpio" },
  314. 				{ ".sv4crc", "application/x-sv4crc" },
  315. 				{ ".svg", "image/svg+xml" },
  316. 				{ ".svgz", "image/svg+xml" },
  317. 				{ ".swf", "application/x-shockwave-flash" },
  318. 				{ ".t", "application/x-troff" },
  319. 				{ ".tar", "application/x-tar" },
  320. 				{ ".tcl", "application/x-tcl" },
  321. 				{ ".tex", "application/x-tex" },
  322. 				{ ".texi", "application/x-texinfo" },
  323. 				{ ".texinfo", "application/x-texinfo" },
  324. 				{ ".tgz", "application/x-compressed" },
  325. 				{ ".thmx", "application/vnd.ms-officetheme" },
  326. 				{ ".thn", "application/octet-stream" },
  327. 				{ ".tif", "image/tiff" },
  328. 				{ ".tiff", "image/tiff" },
  329. 				{ ".toc", "application/octet-stream" },
  330. 				{ ".tr", "application/x-troff" },
  331. 				{ ".trm", "application/x-msterminal" },
  332. 				{ ".ts", "video/vnd.dlna.mpeg-tts" },
  333. 				{ ".tsv", "text/tab-separated-values" },
  334. 				{ ".ttc", "application/x-font-ttf" },
  335. 				{ ".ttf", "application/x-font-ttf" },
  336. 				{ ".tts", "video/vnd.dlna.mpeg-tts" },
  337. 				{ ".txt", "text/plain" },
  338. 				{ ".u32", "application/octet-stream" },
  339. 				{ ".uls", "text/iuls" },
  340. 				{ ".ustar", "application/x-ustar" },
  341. 				{ ".vbs", "text/vbscript" },
  342. 				{ ".vcf", "text/x-vcard" },
  343. 				{ ".vcs", "text/plain" },
  344. 				{ ".vdx", "application/vnd.ms-visio.viewer" },
  345. 				{ ".vml", "text/xml" },
  346. 				{ ".vsd", "application/vnd.visio" },
  347. 				{ ".vss", "application/vnd.visio" },
  348. 				{ ".vst", "application/vnd.visio" },
  349. 				{ ".vsto", "application/x-ms-vsto" },
  350. 				{ ".vsw", "application/vnd.visio" },
  351. 				{ ".vsx", "application/vnd.visio" },
  352. 				{ ".vtx", "application/vnd.visio" },
  353. 				{ ".wasm", "application/wasm" },
  354. 				{ ".wav", "audio/wav" },
  355. 				{ ".wax", "audio/x-ms-wax" },
  356. 				{ ".wbmp", "image/vnd.wap.wbmp" },
  357. 				{ ".wcm", "application/vnd.ms-works" },
  358. 				{ ".wdb", "application/vnd.ms-works" },
  359. 				{ ".webm", "video/webm" },
  360. 				{ ".webmanifest", "application/manifest+json" }, // https://w3c.github.io/manifest/#media-type-registration
  361.                 { ".webp", "image/webp" },
  362. 				{ ".wks", "application/vnd.ms-works" },
  363. 				{ ".wm", "video/x-ms-wm" },
  364. 				{ ".wma", "audio/x-ms-wma" },
  365. 				{ ".wmd", "application/x-ms-wmd" },
  366. 				{ ".wmf", "application/x-msmetafile" },
  367. 				{ ".wml", "text/vnd.wap.wml" },
  368. 				{ ".wmlc", "application/vnd.wap.wmlc" },
  369. 				{ ".wmls", "text/vnd.wap.wmlscript" },
  370. 				{ ".wmlsc", "application/vnd.wap.wmlscriptc" },
  371. 				{ ".wmp", "video/x-ms-wmp" },
  372. 				{ ".wmv", "video/x-ms-wmv" },
  373. 				{ ".wmx", "video/x-ms-wmx" },
  374. 				{ ".wmz", "application/x-ms-wmz" },
  375. 				{ ".woff", "application/font-woff" }, // https://www.w3.org/TR/WOFF/#appendix-b
  376.                 { ".woff2", "font/woff2" }, // https://www.w3.org/TR/WOFF2/#IMT
  377.                 { ".wps", "application/vnd.ms-works" },
  378. 				{ ".wri", "application/x-mswrite" },
  379. 				{ ".wrl", "x-world/x-vrml" },
  380. 				{ ".wrz", "x-world/x-vrml" },
  381. 				{ ".wsdl", "text/xml" },
  382. 				{ ".wtv", "video/x-ms-wtv" },
  383. 				{ ".wvx", "video/x-ms-wvx" },
  384. 				{ ".x", "application/directx" },
  385. 				{ ".xaf", "x-world/x-vrml" },
  386. 				{ ".xaml", "application/xaml+xml" },
  387. 				{ ".xap", "application/x-silverlight-app" },
  388. 				{ ".xbap", "application/x-ms-xbap" },
  389. 				{ ".xbm", "image/x-xbitmap" },
  390. 				{ ".xdr", "text/plain" },
  391. 				{ ".xht", "application/xhtml+xml" },
  392. 				{ ".xhtml", "application/xhtml+xml" },
  393. 				{ ".xla", "application/vnd.ms-excel" },
  394. 				{ ".xlam", "application/vnd.ms-excel.addin.macroEnabled.12" },
  395. 				{ ".xlc", "application/vnd.ms-excel" },
  396. 				{ ".xlm", "application/vnd.ms-excel" },
  397. 				{ ".xls", "application/vnd.ms-excel" },
  398. 				{ ".xlsb", "application/vnd.ms-excel.sheet.binary.macroEnabled.12" },
  399. 				{ ".xlsm", "application/vnd.ms-excel.sheet.macroEnabled.12" },
  400. 				{ ".xlsx", "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet" },
  401. 				{ ".xlt", "application/vnd.ms-excel" },
  402. 				{ ".xltm", "application/vnd.ms-excel.template.macroEnabled.12" },
  403. 				{ ".xltx", "application/vnd.openxmlformats-officedocument.spreadsheetml.template" },
  404. 				{ ".xlw", "application/vnd.ms-excel" },
  405. 				{ ".xml", "text/xml" },
  406. 				{ ".xof", "x-world/x-vrml" },
  407. 				{ ".xpm", "image/x-xpixmap" },
  408. 				{ ".xps", "application/vnd.ms-xpsdocument" },
  409. 				{ ".xsd", "text/xml" },
  410. 				{ ".xsf", "text/xml" },
  411. 				{ ".xsl", "text/xml" },
  412. 				{ ".xslt", "text/xml" },
  413. 				{ ".xsn", "application/octet-stream" },
  414. 				{ ".xtp", "application/octet-stream" },
  415. 				{ ".xwd", "image/x-xwindowdump" },
  416. 				{ ".z", "application/x-compress" },
  417. 				{ ".zip", "application/x-zip-compressed" },
  418. 				})
  419. 			{
  420. 			}
  421. 			#endregion
  423. 			/// <summary>
  424. 			/// Creates a lookup engine using the provided mapping.
  425. 			/// It is recommended that the IDictionary instance use StringComparer.OrdinalIgnoreCase.
  426. 			/// </summary>
  427. 			/// <param name="mapping"></param>
  428. 			public FileExtensionContentTypeProvider(IDictionary<string, string> mapping)
  429. 			{
  430. 				if (mapping == null)
  431. 				{
  432. 					throw new ArgumentNullException(nameof(mapping));
  433. 				}
  434. 				Mappings = mapping;
  435. 			}
  437. 			/// <summary>
  438. 			/// The cross reference table of file extensions and content-types.
  439. 			/// </summary>
  440. 			public IDictionary<string, string> Mappings { get; private set; }
  442. 			/// <summary>
  443. 			/// Given a file path, determine the MIME type
  444. 			/// </summary>
  445. 			/// <param name="subpath">A file path</param>
  446. 			/// <param name="contentType">The resulting MIME type</param>
  447. 			/// <returns>True if MIME type could be determined</returns>
  448. 			public bool TryGetContentType(string subpath, [MaybeNullWhen(false)] out string contentType)
  449. 			{
  450. 				var extension = GetExtension(subpath);
  451. 				if (extension == null)
  452. 				{
  453. 					contentType = null;
  454. 					return false;
  455. 				}
  456. 				return Mappings.TryGetValue(extension, out contentType);
  457. 			}
  459. 			private static string GetExtension(string path)
  460. 			{
  461. 				// Don't use Path.GetExtension as that may throw an exception if there are
  462. 				// invalid characters in the path. Invalid characters should be handled
  463. 				// by the FileProviders
  465. 				if (string.IsNullOrWhiteSpace(path))
  466. 				{
  467. 					return null;
  468. 				}
  470. 				int index = path.LastIndexOf('.');
  471. 				if (index < 0)
  472. 				{
  473. 					return null;
  474. 				}
  476. 				return path.Substring(index);
  477. 			}
  478. 		}
  479. 	}
  480. }

创建自定义的BlazorWebViewHandler类

BlazorWebViewHandler是MAUI Blazor中处理BlazorWebView相关的一个类，我们自定义一个类替换它，添加自己需要的一些处理逻辑

Maui Blazor中iOS / Mac和其他平台的baseUrl是不统一的，iOS / Mac是 app://0.0.0.0 (原因在Maui源码的注释中有写到，iOS WKWebView doesn't allow handling 'http'/'https' schemes, so we use the fake 'app' scheme),其他平台是 https://0.0.0.0 ，所以我们的url设为相对路径才能统一，而且与页面同源，不会有跨域问题(笔者之前在iOS / Mac上的做法就是注册自定义协议，使用html2canvas截图时，结果发生了跨域问题)。

添加MauiBlazorWebViewHandler.cs
代码如下

  1. using Microsoft.AspNetCore.Components.WebView.Maui;
  3. namespace MauiBlazorLocalMediaFile
  4. {
  5.     public partial class MauiBlazorWebViewHandler : BlazorWebViewHandler
  6.     {
  7.         private const string AppHostAddress = "0.0.0.0";
  8. #if IOS || MACCATALYST
  9.         public const string BaseUri = $"app://{AppHostAddress}/";
  10. #else
  11.         public const string BaseUri = $"https://{AppHostAddress}/";
  12. #endif
  13.         public readonly static Dictionary<string, string> AppFilePathMap = new()
  14.         {
  15.             { FileSystem.AppDataDirectory, "appdata" },
  16.             { FileSystem.CacheDirectory, "cache" },
  17.         };
  19.         private static readonly string OtherFileMapPath = "file";
  21.         //把真实的文件路径转化为url相对路径
  22.         public static string FilePathToUrlRelativePath(string filePath)
  23.         {
  24.             foreach (var item in AppFilePathMap)
  25.             {
  26.                 if (filePath.StartsWith(item.Key))
  27.                 {
  28.                     return item.Value + filePath[item.Key.Length..].Replace(Path.DirectorySeparatorChar, '/');
  29.                 }
  30.             }
  32.             return OtherFileMapPath + "/" + Uri.EscapeDataString(filePath);
  33.         }
  35.         //把url相对路径转化为真实的文件路径
  36.         public static string UrlRelativePathToFilePath(string urlRelativePath)
  37.         {
  38.             UrlRelativePathToFilePath(urlRelativePath, out string path);
  39.             return path;
  40.         }
  42.         private static bool Intercept(string uri, out string path)
  43.         {
  44.             if (!uri.StartsWith(BaseUri))
  45.             {
  46.                 path = string.Empty;
  47.                 return false;
  48.             }
  50.             var urlRelativePath = uri[BaseUri.Length..];
  51.             return UrlRelativePathToFilePath(urlRelativePath, out path);
  52.         }
  54.         private static bool UrlRelativePathToFilePath(string urlRelativePath, out string path)
  55.         {
  56.             if (string.IsNullOrEmpty(urlRelativePath))
  57.             {
  58.                 path = string.Empty;
  59.                 return false;
  60.             }
  62.             urlRelativePath = Uri.UnescapeDataString(urlRelativePath);
  64.             foreach (var item in AppFilePathMap)
  65.             {
  66.                 if (urlRelativePath.StartsWith(item.Value + '/'))
  67.                 {
  68.                     string urlRelativePathSub = urlRelativePath[(item.Value.Length + 1)..];
  69.                     path = Path.Combine(item.Key, urlRelativePathSub.Replace('/', Path.DirectorySeparatorChar));
  70.                     if (File.Exists(path))
  71.                     {
  72.                         return true;
  73.                     }
  74.                 }
  75.             }
  77.             if (urlRelativePath.StartsWith(OtherFileMapPath + '/'))
  78.             {
  79.                 string urlRelativePathSub = urlRelativePath[(OtherFileMapPath.Length + 1)..];
  80.                 path = urlRelativePathSub.Replace('/', Path.DirectorySeparatorChar);
  81.                 if (File.Exists(path))
  82.                 {
  83.                     return true;
  84.                 }
  85.             }
  87.             path = string.Empty;
  88.             return false;
  89.         }
  90.     }
  91. }
Android

添加MauiBlazorWebViewHandler.Android.cs
代码如下

  1. using Android.Webkit;
  2. using MauiBlazorLocalMediaFile.Utilities;
  3. using WebView = Android.Webkit.WebView;
  5. namespace MauiBlazorLocalMediaFile
  6. {
  7.     public partial class MauiBlazorWebViewHandler
  8.     {
  9. #pragma warning disable CA1416 // 验证平台兼容性
  10.         protected override void ConnectHandler(WebView platformView)
  11.         {
  12.             base.ConnectHandler(platformView);
  13.             platformView.SetWebViewClient(new MyWebViewClient(platformView.WebViewClient));
  14.         }
  16. #nullable disable
  17.         private class MyWebViewClient : WebViewClient
  18.         {
  19.             private WebViewClient WebViewClient { get; }
  21.             public MyWebViewClient(WebViewClient webViewClient)
  22.             {
  23.                 WebViewClient = webViewClient;
  24.             }
  26.             public override bool ShouldOverrideUrlLoading(Android.Webkit.WebView view, IWebResourceRequest request)
  27.             {
  28.                 return WebViewClient.ShouldOverrideUrlLoading(view, request);
  29.             }
  31.             public override WebResourceResponse ShouldInterceptRequest(Android.Webkit.WebView view, IWebResourceRequest request)
  32.             {
  33.                 var intercept = InterceptCustomPathRequest(request, out WebResourceResponse webResourceResponse);
  34.                 if (intercept)
  35.                 {
  36.                     return webResourceResponse;
  37.                 }
  39.                 return WebViewClient.ShouldInterceptRequest(view, request);
  40.             }
  42.             public override void OnPageFinished(Android.Webkit.WebView view, string url)
  43.                 => WebViewClient.OnPageFinished(view, url);
  45.             protected override void Dispose(bool disposing)
  46.             {
  47.                 if (!disposing)
  48.                     return;
  50.                 WebViewClient.Dispose();
  51.             }
  53.             private static bool InterceptCustomPathRequest(IWebResourceRequest request, out WebResourceResponse webResourceResponse)
  54.             {
  55.                 webResourceResponse = null;
  57.                 var uri = request.Url.ToString();
  58.                 if (!Intercept(uri, out string path))
  59.                 {
  60.                     return false;
  61.                 }
  63.                 if (!File.Exists(path))
  64.                 {
  65.                     return false;
  66.                 }
  68.                 webResourceResponse = CreateWebResourceResponse(request, path);
  69.                 return true;
  70.             }
  72.             private static WebResourceResponse CreateWebResourceResponse(IWebResourceRequest request, string path)
  73.             {
  74.                 string contentType = StaticContentProvider.GetResponseContentTypeOrDefault(path);
  75.                 var headers = StaticContentProvider.GetResponseHeaders(contentType);
  76.                 FileStream stream = File.OpenRead(path);
  77.                 var length = stream.Length;
  78.                 long rangeStart = 0;
  79.                 long rangeEnd = length - 1;
  81.                 string encoding = "UTF-8";
  82.                 int stateCode = 200;
  83.                 string reasonPhrase = "OK";
  85.                 //适用于音频视频文件资源的响应
  86.                 bool partial = request.RequestHeaders.TryGetValue("Range", out string rangeString);
  87.                 if (partial)
  88.                 {
  89.                     //206,可断点续传
  90.                     stateCode = 206;
  91.                     reasonPhrase = "Partial Content";
  93.                     var ranges = rangeString.Split('=');
  94.                     if (ranges.Length > 1 && !string.IsNullOrEmpty(ranges[1]))
  95.                     {
  96.                         string[] rangeDatas = ranges[1].Split("-");
  97.                         rangeStart = Convert.ToInt64(rangeDatas[0]);
  98.                         if (rangeDatas.Length > 1 && !string.IsNullOrEmpty(rangeDatas[1]))
  99.                         {
  100.                             rangeEnd = Convert.ToInt64(rangeDatas[1]);
  101.                         }
  102.                     }
  104.                     headers.Add("Accept-Ranges", "bytes");
  105.                     headers.Add("Content-Range", $"bytes {rangeStart}-{rangeEnd}/{length}");
  106.                 }
  108.                 //这一行删去似乎也不影响
  109.                 headers.Add("Content-Length", (rangeEnd - rangeStart + 1).ToString());
  111.                 var response = new WebResourceResponse(contentType, encoding, stateCode, reasonPhrase, headers, stream);
  112.                 return response;
  113.             }
  115.         }
  116.     }
  117. }
iOS / Mac

iOS / Mac中我们要替换Maui对于app://自定义协议的注册，但是很多类、方法、属性、字段是不公开的，也就是internal和private，所以我们的代码用了很多反射。

添加 MauiBlazorWebViewHandler.MaciOS.cs
代码如下

  1. using Foundation;
  2. using Microsoft.AspNetCore.Components.WebView;
  3. using Microsoft.AspNetCore.Components.WebView.Maui;
  4. using Microsoft.Extensions.Logging;
  5. using MauiBlazorLocalMediaFile.Utilities;
  6. using System.Globalization;
  7. using System.Reflection;
  8. using System.Runtime.Versioning;
  9. using UIKit;
  10. using WebKit;
  11. using RectangleF = CoreGraphics.CGRect;
  13. namespace MauiBlazorLocalMediaFile
  14. {
  15. #nullable disable
  16.     public partial class MauiBlazorWebViewHandler
  17.     {
  18.         private BlazorWebViewHandlerReflection _base;
  20.         private BlazorWebViewHandlerReflection Base => _base ??= new(this);
  22.         [SupportedOSPlatform("ios11.0")]
  23.         protected override WKWebView CreatePlatformView()
  24.         {
  25.             Base.LoggerCreatingWebKitWKWebView();
  27.             var config = new WKWebViewConfiguration();
  29.             // By default, setting inline media playback to allowed, including autoplay
  30.             // and picture in picture, since these things MUST be set during the webview
  31.             // creation, and have no effect if set afterwards.
  32.             // A custom handler factory delegate could be set to disable these defaults
  33.             // but if we do not set them here, they cannot be changed once the
  34.             // handler's platform view is created, so erring on the side of wanting this
  35.             // capability by default.
  36.             if (OperatingSystem.IsMacCatalystVersionAtLeast(10) || OperatingSystem.IsIOSVersionAtLeast(10))
  37.             {
  38.                 config.AllowsPictureInPictureMediaPlayback = true;
  39.                 config.AllowsInlineMediaPlayback = true;
  40.                 config.MediaTypesRequiringUserActionForPlayback = WKAudiovisualMediaTypes.None;
  41.             }
  43.             VirtualView.BlazorWebViewInitializing(new BlazorWebViewInitializingEventArgs()
  44.             {
  45.                 Configuration = config
  46.             });
  48.             // Legacy Developer Extras setting.
  49.             config.Preferences.SetValueForKey(NSObject.FromObject(Base.DeveloperToolsEnabled), new NSString("developerExtrasEnabled"));
  51.             config.UserContentController.AddScriptMessageHandler(Base.CreateWebViewScriptMessageHandler(), "webwindowinterop");
  52.             config.UserContentController.AddUserScript(new WKUserScript(
  53.                 new NSString(Base.BlazorInitScript), WKUserScriptInjectionTime.AtDocumentEnd, true));
  55.             // iOS WKWebView doesn't allow handling 'http'/'https' schemes, so we use the fake 'app' scheme
  56.             config.SetUrlSchemeHandler(new SchemeHandler(this), urlScheme: "app");
  58.             var webview = new WKWebView(RectangleF.Empty, config)
  59.             {
  60.                 BackgroundColor = UIColor.Clear,
  61.                 AutosizesSubviews = true
  62.             };
  64.             if (OperatingSystem.IsIOSVersionAtLeast(16, 4) || OperatingSystem.IsMacCatalystVersionAtLeast(13, 3))
  65.             {
  66.                 // Enable Developer Extras for Catalyst/iOS builds for 16.4+
  67.                 webview.SetValueForKey(NSObject.FromObject(Base.DeveloperToolsEnabled), new NSString("inspectable"));
  68.             }
  70.             VirtualView.BlazorWebViewInitialized(Base.CreateBlazorWebViewInitializedEventArgs(webview));
  72.             Base.LoggerCreatedWebKitWKWebView();
  74.             return webview;
  75.         }
  77.         private class SchemeHandler : NSObject, IWKUrlSchemeHandler
  78.         {
  79.             private readonly MauiBlazorWebViewHandler _webViewHandler;
  81.             public SchemeHandler(MauiBlazorWebViewHandler webViewHandler)
  82.             {
  83.                 _webViewHandler = webViewHandler;
  84.             }
  86.             [Export("webView:startURLSchemeTask:")]
  87.             [SupportedOSPlatform("ios11.0")]
  88.             public void StartUrlSchemeTask(WKWebView webView, IWKUrlSchemeTask urlSchemeTask)
  89.             {
  90.                 var intercept = InterceptCustomPathRequest(urlSchemeTask);
  91.                 if (intercept)
  92.                 {
  93.                     return;
  94.                 }
  96.                 var responseBytes = GetResponseBytes(urlSchemeTask.Request.Url?.AbsoluteString ?? "", out var contentType, statusCode: out var statusCode);
  97.                 if (statusCode == 200)
  98.                 {
  99.                     using (var dic = new NSMutableDictionary<NSString, NSString>())
  100.                     {
  101.                         dic.Add((NSString)"Content-Length", (NSString)(responseBytes.Length.ToString(CultureInfo.InvariantCulture)));
  102.                         dic.Add((NSString)"Content-Type", (NSString)contentType);
  103.                         // Disable local caching. This will prevent user scripts from executing correctly.
  104.                         dic.Add((NSString)"Cache-Control", (NSString)"no-cache, max-age=0, must-revalidate, no-store");
  105.                         if (urlSchemeTask.Request.Url != null)
  106.                         {
  107.                             using var response = new NSHttpUrlResponse(urlSchemeTask.Request.Url, statusCode, "HTTP/1.1", dic);
  108.                             urlSchemeTask.DidReceiveResponse(response);
  109.                         }
  111.                     }
  112.                     urlSchemeTask.DidReceiveData(NSData.FromArray(responseBytes));
  113.                     urlSchemeTask.DidFinish();
  114.                 }
  115.             }
  117.             private byte[] GetResponseBytes(string? url, out string contentType, out int statusCode)
  118.             {
  119.                 var allowFallbackOnHostPage = _webViewHandler.Base.IsBaseOfPage(_webViewHandler.Base.AppOriginUri, url);
  120.                 url = _webViewHandler.Base.QueryStringHelperRemovePossibleQueryString(url);
  122.                 _webViewHandler.Base.LoggerHandlingWebRequest(url);
  124.                 if (_webViewHandler.Base.TryGetResponseContentInternal(url, allowFallbackOnHostPage, out statusCode, out var statusMessage, out var content, out var headers))
  125.                 {
  126.                     statusCode = 200;
  127.                     using var ms = new MemoryStream();
  129.                     content.CopyTo(ms);
  130.                     content.Dispose();
  132.                     contentType = headers["Content-Type"];
  134.                     _webViewHandler?.Base.LoggerResponseContentBeingSent(url, statusCode);
  136.                     return ms.ToArray();
  137.                 }
  138.                 else
  139.                 {
  140.                     _webViewHandler?.Base.LoggerReponseContentNotFound(url);
  142.                     statusCode = 404;
  143.                     contentType = string.Empty;
  144.                     return Array.Empty<byte>();
  145.                 }
  146.             }
  148.             [Export("webView:stopURLSchemeTask:")]
  149.             public void StopUrlSchemeTask(WKWebView webView, IWKUrlSchemeTask urlSchemeTask)
  150.             {
  151.             }
  153.             private static bool InterceptCustomPathRequest(IWKUrlSchemeTask urlSchemeTask)
  154.             {
  155.                 var uri = urlSchemeTask.Request.Url.ToString();
  156.                 if (uri == null)
  157.                 {
  158.                     return false;
  159.                 }
  161.                 if (!Intercept(uri, out string path))
  162.                 {
  163.                     return false;
  164.                 }
  166.                 if (!File.Exists(path))
  167.                 {
  168.                     return false;
  169.                 }
  171.                 long length = new FileInfo(path).Length;
  172.                 string contentType = StaticContentProvider.GetResponseContentTypeOrDefault(path);
  173.                 using (var dic = new NSMutableDictionary<NSString, NSString>())
  174.                 {
  175.                     dic.Add((NSString)"Content-Length", (NSString)(length.ToString(CultureInfo.InvariantCulture)));
  176.                     dic.Add((NSString)"Content-Type", (NSString)contentType);
  177.                     // Disable local caching. This will prevent user scripts from executing correctly.
  178.                     dic.Add((NSString)"Cache-Control", (NSString)"no-cache, max-age=0, must-revalidate, no-store");
  179.                     using var response = new NSHttpUrlResponse(urlSchemeTask.Request.Url, 200, "HTTP/1.1", dic);
  180.                     urlSchemeTask.DidReceiveResponse(response);
  181.                 }
  183.                 urlSchemeTask.DidReceiveData(NSData.FromFile(path));
  184.                 urlSchemeTask.DidFinish();
  185.                 return true;
  186.             }
  187.         }
  188.     }
  190.     public class BlazorWebViewHandlerReflection
  191.     {
  192.         public BlazorWebViewHandlerReflection(BlazorWebViewHandler blazorWebViewHandler)
  193.         {
  194.             _blazorWebViewHandler = blazorWebViewHandler;
  195.             _logger = new(() =>
  196.             {
  197.                 var property = Type.GetProperty("Logger", BindingFlags.NonPublic | BindingFlags.Instance);
  198.                 return (ILogger)property?.GetValue(_blazorWebViewHandler);
  199.             });
  200.             _blazorInitScript = new(() =>
  201.             {
  202.                 var property = Type.GetField("BlazorInitScript", BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.Static);
  203.                 return (string)property?.GetValue(_blazorWebViewHandler);
  204.             });
  205.             _appOriginUri = new(() =>
  206.             {
  207.                 var property = Type.GetField("AppOriginUri", BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.Static);
  208.                 return (Uri)property?.GetValue(_blazorWebViewHandler);
  209.             });
  210.         }
  212.         private readonly BlazorWebViewHandler _blazorWebViewHandler;
  214.         private static readonly Type Type = typeof(BlazorWebViewHandler);
  216.         private static readonly Assembly Assembly = Type.Assembly;
  218.         private static readonly Type TypeLog = Assembly.GetType("Microsoft.AspNetCore.Components.WebView.Log")!;
  220.         private readonly Lazy<ILogger> _logger;
  222.         private readonly Lazy<string> _blazorInitScript;
  224.         private readonly Lazy<Uri> _appOriginUri;
  226.         private object WebviewManager;
  228.         private MethodInfo MethodTryGetResponseContentInternal;
  230.         private MethodInfo MethodIsBaseOfPage;
  232.         private MethodInfo MethodQueryStringHelperRemovePossibleQueryString;
  234.         public ILogger Logger => _logger.Value;
  236.         public string BlazorInitScript => _blazorInitScript.Value;
  238.         public Uri AppOriginUri => _appOriginUri.Value;
  240.         public bool DeveloperToolsEnabled => GetDeveloperToolsEnabled();
  242.         public void LoggerCreatingWebKitWKWebView()
  243.         {
  244.             var method = TypeLog.GetMethod("CreatingWebKitWKWebView");
  245.             method?.Invoke(null, new object[] { Logger });
  246.         }
  248.         public void LoggerCreatedWebKitWKWebView()
  249.         {
  250.             var method = TypeLog.GetMethod("CreatedWebKitWKWebView");
  251.             method?.Invoke(null, new object[] { Logger });
  252.         }
  254.         public void LoggerHandlingWebRequest(string url)
  255.         {
  256.             var method = TypeLog.GetMethod("HandlingWebRequest");
  257.             method?.Invoke(null, new object[] { Logger, url });
  258.         }
  260.         public void LoggerResponseContentBeingSent(string url, int statusCode)
  261.         {
  262.             var method = TypeLog.GetMethod("ResponseContentBeingSent");
  263.             method?.Invoke(null, new object[] { Logger, url, statusCode });
  264.         }
  266.         public void LoggerReponseContentNotFound(string url)
  267.         {
  268.             var method = TypeLog.GetMethod("ReponseContentNotFound");
  269.             method?.Invoke(null, new object[] { Logger, url });
  270.         }
  272.         private bool GetDeveloperToolsEnabled()
  273.         {
  274.             var PropertyDeveloperTools = Type.GetProperty("DeveloperTools", BindingFlags.NonPublic | BindingFlags.Instance);
  275.             var DeveloperTools = PropertyDeveloperTools.GetValue(_blazorWebViewHandler);
  277.             var type = DeveloperTools.GetType();
  278.             var Enabled = type.GetProperty("Enabled", BindingFlags.Public | BindingFlags.Instance);
  279.             return (bool)Enabled?.GetValue(DeveloperTools);
  280.         }
  282.         public IWKScriptMessageHandler CreateWebViewScriptMessageHandler()
  283.         {
  284.             Type webViewScriptMessageHandlerType = Type.GetNestedType("WebViewScriptMessageHandler", BindingFlags.NonPublic);
  286.             if (webViewScriptMessageHandlerType != null)
  287.             {
  288.                 // 获取 MessageReceived 方法信息
  289.                 MethodInfo messageReceivedMethod = Type.GetMethod("MessageReceived", BindingFlags.Instance | BindingFlags.NonPublic);
  291.                 if (messageReceivedMethod != null)
  292.                 {
  293.                     // 创建 WebViewScriptMessageHandler 实例
  294.                     object webViewScriptMessageHandlerInstance = Activator.CreateInstance(webViewScriptMessageHandlerType, new object[] { Delegate.CreateDelegate(typeof(Action<Uri, string>), _blazorWebViewHandler, messageReceivedMethod) });
  295.                     return (IWKScriptMessageHandler)webViewScriptMessageHandlerInstance;
  296.                 }
  297.             }
  299.             return null;
  300.         }
  302.         public BlazorWebViewInitializedEventArgs CreateBlazorWebViewInitializedEventArgs(WKWebView wKWebView)
  303.         {
  304.             var blazorWebViewInitializedEventArgs = new BlazorWebViewInitializedEventArgs();
  305.             PropertyInfo property = typeof(BlazorWebViewInitializedEventArgs).GetProperty("WebView", BindingFlags.Public | BindingFlags.Instance);
  306.             property.SetValue(blazorWebViewInitializedEventArgs, wKWebView);
  307.             return blazorWebViewInitializedEventArgs;
  308.         }
  310.         public bool TryGetResponseContentInternal(string uri, bool allowFallbackOnHostPage, out int statusCode, out string statusMessage, out Stream content, out IDictionary<string, string> headers)
  311.         {
  312.             if (MethodTryGetResponseContentInternal == null)
  313.             {
  314.                 var Field_webviewManager = Type.GetField("_webviewManager", BindingFlags.NonPublic | BindingFlags.Instance);
  315.                 WebviewManager = Field_webviewManager.GetValue(_blazorWebViewHandler);
  317.                 MethodTryGetResponseContentInternal = WebviewManager.GetType().GetMethod("TryGetResponseContentInternal", BindingFlags.NonPublic | BindingFlags.Instance);
  318.             }
  319.             // 定义参数
  320.             object[] parameters = new object[] { uri, allowFallbackOnHostPage, 0, null, null, null };
  322.             bool result = (bool)MethodTryGetResponseContentInternal.Invoke(WebviewManager, parameters);
  324.             // 获取返回值和输出参数
  325.             statusCode = (int)parameters[2];
  326.             statusMessage = (string)parameters[3];
  327.             content = (Stream)parameters[4];
  328.             headers = (IDictionary<string, string>)parameters[5];
  329.             return result;
  330.         }
  332.         public bool IsBaseOfPage(Uri baseUri, string? uriString)
  333.         {
  334.             if (MethodIsBaseOfPage == null)
  335.             {
  336.                 var type = Assembly.GetType("Microsoft.AspNetCore.Components.WebView.Maui.UriExtensions")!;
  337.                 MethodIsBaseOfPage = type.GetMethod("IsBaseOfPage", BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.Static);
  338.             }
  340.             return (bool)MethodIsBaseOfPage.Invoke(null, new object[] { baseUri, uriString });
  341.         }
  343.         public string QueryStringHelperRemovePossibleQueryString(string? url)
  344.         {
  345.             if (MethodQueryStringHelperRemovePossibleQueryString == null)
  346.             {
  347.                 var type = Assembly.GetType("Microsoft.AspNetCore.Components.WebView.QueryStringHelper")!;
  348.                 MethodQueryStringHelperRemovePossibleQueryString = type.GetMethod("RemovePossibleQueryString", BindingFlags.Public | BindingFlags.Static | BindingFlags.Instance);
  349.             }
  351.             return (string)MethodQueryStringHelperRemovePossibleQueryString.Invoke(null, new object[] { url });
  352.         }
  353.     }
  354. }
Windows

添加MauiBlazorWebViewHandler.Windows.cs
代码如下

  1. using MauiBlazorLocalMediaFile.Utilities;
  2. using Microsoft.Web.WebView2.Core;
  3. using System.Runtime.InteropServices.WindowsRuntime;
  4. using Windows.Storage.Streams;
  5. using WebView2Control = Microsoft.UI.Xaml.Controls.WebView2;
  7. namespace MauiBlazorLocalMediaFile
  8. {
  9.     public partial class MauiBlazorWebViewHandler
  10.     {
  11.         protected override void ConnectHandler(WebView2Control platformView)
  12.         {
  13.             base.ConnectHandler(platformView);
  14.             platformView.CoreWebView2Initialized += CoreWebView2Initialized;
  15.         }
  17.         protected override void DisconnectHandler(WebView2Control platformView)
  18.         {
  19.             platformView.CoreWebView2Initialized -= CoreWebView2Initialized;
  20.             base.DisconnectHandler(platformView);
  21.         }
  23.         private void CoreWebView2Initialized(WebView2Control sender, Microsoft.UI.Xaml.Controls.CoreWebView2InitializedEventArgs args)
  24.         {
  25.             var webview2 = sender.CoreWebView2;
  26.             webview2.WebResourceRequested += WebView2WebResourceRequested;
  27.         }
  29.         async void WebView2WebResourceRequested(CoreWebView2 webview2, CoreWebView2WebResourceRequestedEventArgs args)
  30.         {
  31.             await InterceptCustomPathRequest(webview2, args);
  32.         }
  34.         static async Task<bool> InterceptCustomPathRequest(CoreWebView2 webview2, CoreWebView2WebResourceRequestedEventArgs args)
  35.         {
  36.             string uri = args.Request.Uri;
  37.             if (!Intercept(uri, out string filePath))
  38.             {
  39.                 return false;
  40.             }
  42.             if (File.Exists(filePath))
  43.             {
  44.                 args.Response = await CreateWebResourceResponse(webview2, args, filePath);
  45.             }
  46.             else
  47.             {
  48.                 args.Response = webview2.Environment.CreateWebResourceResponse(null, 404, "Not Found", string.Empty);
  49.             }
  51.             return true;
  53.             static string GetHeaderString(IDictionary<string, string> headers) =>
  54.                 string.Join(Environment.NewLine, headers.Select(kvp => $"{kvp.Key}: {kvp.Value}"));
  56.             static async Task<CoreWebView2WebResourceResponse> CreateWebResourceResponse(CoreWebView2 webview2, CoreWebView2WebResourceRequestedEventArgs args, string filePath)
  57.             {
  58.                 var contentType = StaticContentProvider.GetResponseContentTypeOrDefault(filePath);
  59.                 var headers = StaticContentProvider.GetResponseHeaders(contentType);
  60.                 using var contentStream = File.OpenRead(filePath);
  61.                 var length = contentStream.Length;
  62.                 long rangeStart = 0;
  63.                 long rangeEnd = length - 1;
  65.                 int statusCode = 200;
  66.                 string reasonPhrase = "OK";
  68.                 //适用于音频视频文件资源的响应
  69.                 bool partial = args.Request.Headers.Contains("Range");
  70.                 if (partial)
  71.                 {
  72.                     statusCode = 206;
  73.                     reasonPhrase = "Partial Content";
  75.                     var rangeString = args.Request.Headers.GetHeader("Range");
  76.                     var ranges = rangeString.Split('=');
  77.                     if (ranges.Length > 1 && !string.IsNullOrEmpty(ranges[1]))
  78.                     {
  79.                         string[] rangeDatas = ranges[1].Split("-");
  80.                         rangeStart = Convert.ToInt64(rangeDatas[0]);
  81.                         if (rangeDatas.Length > 1 && !string.IsNullOrEmpty(rangeDatas[1]))
  82.                         {
  83.                             rangeEnd = Convert.ToInt64(rangeDatas[1]);
  84.                         }
  85.                         else
  86.                         {
  87.                             //每次加载4Mb，不能设置太多
  88.                             rangeEnd = Math.Min(rangeEnd, rangeStart + 4 * 1024 * 1024);
  89.                         }
  90.                     }
  92.                     headers.Add("Accept-Ranges", "bytes");
  93.                     headers.Add("Content-Range", $"bytes {rangeStart}-{rangeEnd}/{length}");
  94.                 }
  96.                 headers.Add("Content-Length", (rangeEnd - rangeStart + 1).ToString());
  97.                 var headerString = GetHeaderString(headers);
  98.                 IRandomAccessStream stream = await ReadStreamRange(contentStream, rangeStart, rangeEnd);
  99.                 return webview2.Environment.CreateWebResourceResponse(stream, statusCode, reasonPhrase, headerString);
  100.             }
  102.             static async Task<IRandomAccessStream> ReadStreamRange(Stream contentStream, long start, long end)
  103.             {
  104.                 long length = end - start + 1;
  105.                 contentStream.Position = start;
  107.                 using var memoryStream = new MemoryStream();
  109.                 StreamCopy(contentStream, memoryStream, length);
  110.                 // 将内存流的位置重置为起始位置
  111.                 memoryStream.Seek(0, SeekOrigin.Begin);
  113.                 var randomAccessStream = new InMemoryRandomAccessStream();
  114.                 await randomAccessStream.WriteAsync(memoryStream.GetWindowsRuntimeBuffer());
  116.                 return randomAccessStream;
  117.             }
  119.             // 辅助方法，用于限制StreamCopy复制的数据长度
  120.             static void StreamCopy(Stream source, Stream destination, long length)
  121.             {
  122.                 //缓冲区设为1Mb,应该是够了
  123.                 byte[] buffer = new byte[1024 * 1024];
  124.                 int bytesRead;
  126.                 while (length > 0 && (bytesRead = source.Read(buffer, 0, (int)Math.Min(buffer.Length, length))) > 0)
  127.                 {
  128.                     destination.Write(buffer, 0, bytesRead);
  129.                     length -= bytesRead;
  130.                 }
  131.             }
  132.         }
  133.     }
  134. }

在MauiProgram.cs中添加

添加在builder.Services.AddMauiBlazorWebView();的下面

  1. builder.Services.ConfigureMauiHandlers(delegate (IMauiHandlersCollection handlers)
  2. {
  3.     handlers.AddHandler<IBlazorWebView>((IServiceProvider _) => new MauiBlazorWebViewHandler());
  4. });

试验一下

添加一个复制文件的静态类

简单写一个方法，用于把选中的文件复制到指定目录，并且返回所需要的url相对路径
为了防止文件被重复复制，我们以md5作为文件名

添加文件夹Utilities/File，在里面添加一个静态类MediaResourceFile.cs
代码如下

  1. using System.Security.Cryptography;
  3. namespace MauiBlazorLocalMediaFile.Utilities
  4. {
  5.     public static class MediaResourceFile
  6.     {
  7.         public static async Task<string?> CreateMediaResourceFileAsync(string targetDirectoryPath, string? sourceFilePath)
  8.         {
  9.             if (string.IsNullOrEmpty(sourceFilePath))
  10.             {
  11.                 return null;
  12.             }
  14.             using Stream stream = File.OpenRead(sourceFilePath);
  15.             //新的文件以文件的md5为文件名，确保文件不会重复存在
  16.             //获取文件的md5有一点耗时，暂时没想到更好的方案
  17.             var fn = stream.CreateMD5() + Path.GetExtension(sourceFilePath);
  18.             var targetFilePath = Path.Combine(targetDirectoryPath, fn);
  19.             //如果文件存在就不用复制了
  20.             if (!File.Exists(targetFilePath))
  21.             {
  22.                 if (sourceFilePath.StartsWith(FileSystem.CacheDirectory))
  23.                 {
  24.                     stream.Close();
  25.                     await FileMoveAsync(sourceFilePath, targetFilePath);
  26.                 }
  27.                 else
  28.                 {
  29.                     //将流的位置重置为起始位置
  30.                     stream.Seek(0, SeekOrigin.Begin);
  31.                     await FileCopyAsync(targetFilePath, stream);
  32.                 }
  33.             }
  35.             return MauiBlazorWebViewHandler.FilePathToUrlRelativePath(targetFilePath);
  36.         }
  38.         private static async Task FileCopyAsync(string targetFilePath, Stream sourceStream)
  39.         {
  40.             CreateFileDirectory(targetFilePath);
  42.             using (FileStream localFileStream = File.OpenWrite(targetFilePath))
  43.             {
  44.                 await sourceStream.CopyToAsync(localFileStream, 1024 * 1024);
  45.             };
  46.         }
  48.         private static Task FileMoveAsync(string sourceFilePath, string targetFilePath)
  49.         {
  50.             CreateFileDirectory(targetFilePath);
  51.             File.Move(sourceFilePath, targetFilePath);
  52.             return Task.CompletedTask;
  53.         }
  55.         private static void CreateFileDirectory(string filePath)
  56.         {
  57.             string? directoryPath = Path.GetDirectoryName(filePath);
  58.             if (!Directory.Exists(directoryPath))
  59.             {
  60.                 Directory.CreateDirectory(directoryPath!);
  61.             }
  62.         }
  64.         private static string CreateMD5(this Stream stream, int bufferSize = 1024 * 1024)
  65.         {
  66.             using MD5 md5 = MD5.Create();
  67.             byte[] buffer = new byte[bufferSize];
  68.             int bytesRead;
  70.             while ((bytesRead = stream.Read(buffer, 0, buffer.Length)) > 0)
  71.             {
  72.                 md5.TransformBlock(buffer, 0, bytesRead, buffer, 0);
  73.             }
  75.             md5.TransformFinalBlock(buffer, 0, 0);
  76.             
  77.             byte[] hash = md5.Hash ?? [];
  78.             return BitConverter.ToString(hash).Replace("-", "").ToLower();
  79.         }
  80.     }
  81. }
写一个选中视频文件并显示的示例页面
  1. @page "/video"
  2. @using MauiBlazorLocalMediaFile.Utilities
  4. <h1>Video</h1>
  6. <video src="@Src" controls style="max-width:100%;"></video>
  8. <div style="word-break: break-all;">Src="@Src"</div>
  10. <button class="btn btn-primary" @onclick="()=>Pick(true)">选中并复制到AppDataDirectory</button>
  11. <button class="btn btn-primary" @onclick="()=>Pick(false)">选中不复制(仅限Windows)</button>
  13. @code {
  14.     private string? Src;
  16.     private async void Pick(bool copy)
  17.     {
  18. #if !WINDOWS
  19.         if (!copy)
  20.         {
  21.             return;
  22.         }
  23. #endif
  25.         var result = await MediaPicker.Default.PickVideoAsync();
  26.         var path = result?.FullPath;
  27.         if (path is null)
  28.         {
  29.             return;
  30.         }
  32.         if (copy)
  33.         {
  34.             var targetDirectoryPath = Path.Combine(FileSystem.AppDataDirectory, "Video");
  35.             Src = await MediaResourceFile.CreateMediaResourceFileAsync(targetDirectoryPath, path);
  36.         }
  37.         else
  38.         {
  39.             Src = MauiBlazorWebViewHandler.FilePathToUrlRelativePath(path);
  40.         }
  42.         await InvokeAsync(StateHasChanged);
  43.     }
  44. }
截图

用笔者比较喜欢的动画电影《魁拔》作为视频文件，大约500MB多一些

Windows

image

Android

iOS / Mac选中视频会被压缩，特别慢，所以就用一个短的视频了

iOS

Mac

image

后来补的一张音频的截图，用的原始路径

image

后记

这篇文章改了又改，总觉得有不妥之处。实在改不动了，就这么地吧，可能写的还是不够详细。

笔者水平有限，性能上可能还存在优化的空间，希望各位大佬不吝赐教，提出宝贵意见

源码

本文中的例子的源码放到 Github 和 Gitee 了

有需要的可以去看一下

Github： https://github.com/Yu-Core/MauiBlazorLocalMediaFile

Gitee： https://gitee.com/Yu-core/MauiBlazorLocalMediaFile

原文链接：https://www.cnblogs.com/Yu-Core/p/17855661.html

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