2.1.0

CHANGELOG.md

@@ -1,3 +1,7 @@
+# 2.1.0
+* Include support for the `Range` header.
+* Use MD5 for etags, instead of a weak ETag.
+
 # 2.0.2
 * Fixed invalid HTML for directory listings.
 

README.md

@@ -2,7 +2,9 @@
 [![Pub](https://img.shields.io/pub/v/angel_static.svg)](https://pub.dartlang.org/packages/angel_static)
 [![build status](https://travis-ci.org/angel-dart/static.svg?branch=master)](https://travis-ci.org/angel-dart/static)
 
-Static server middleware for Angel.
+Static server infrastructure for Angel.
+
+*Can also handle `Range` requests now, making it suitable for media streaming, ex. music, video, etc.*
 
 # Installation
 In `pubspec.yaml`:

lib/src/cache.dart

@@ -1,13 +1,14 @@
 import 'dart:async';
-import 'dart:convert';
 import 'dart:io' show HttpDate;
 import 'package:angel_framework/angel_framework.dart';
+import 'package:convert/convert.dart';
+import 'package:crypto/crypto.dart';
 import 'package:file/file.dart';
 import 'virtual_directory.dart';
 
-/// Generates a weak ETag from the given buffer.
+/// Generates an MD5 ETag from the given buffer.
-String weakEtag(List<int> buf) {
+String md5Etag(List<int> buf) {
-  return 'W/${buf.length}' + base64Url.encode(buf.take(50).toList());
+  return hex.encode(md5.convert(buf).bytes);
 }
 
 /// Returns a string representation of the given [CacheAccessLevel].
@@ -67,6 +68,8 @@ class CachingVirtualDirectory extends VirtualDirectory {
   @override
   Future<bool> serveFile(
       File file, FileStat stat, RequestContext req, ResponseContext res) {
+    res.headers['accept-ranges'] = 'bytes';
+
     if (onlyInProduction == true && req.app.isProduction != true) {
       return super.serveFile(file, stat, req, res);
     }
@@ -82,8 +85,55 @@ class CachingVirtualDirectory extends VirtualDirectory {
       res.headers['cache-control'] = 'private, max-age=0, no-cache';
       return super.serveFile(file, stat, req, res);
     } else {
+      var ifModified = req.headers.ifModifiedSince;
+      bool ifRange = false;
+
+      try {
+        ifModified = HttpDate.parse(req.headers.value('if-range'));
+        ifRange = true;
+      } catch (_) {
+        // Fail silently...
+      }
+
+      if (ifModified != null) {
+        try {
+          var ifModifiedSince = ifModified;
+
+          if (ifModifiedSince.compareTo(stat.modified) >= 0) {
+            res.statusCode = 304;
+            setCachedHeaders(stat.modified, req, res);
+
+            if (useEtags && _etags.containsKey(file.absolute.path))
+              res.headers['ETag'] = _etags[file.absolute.path];
+
+            if (ifRange) {
+              // Send the 206 like normal
+              res.statusCode = 206;
+              return super.serveFile(file, stat, req, res);
+            }
+
+            return new Future.value(false);
+          } else if (ifRange) {
+            // Return 200, just send the whole thing.
+            return res.streamFile(file).then((_) => false);
+          }
+        } catch (_) {
+          throw new AngelHttpException.badRequest(
+              message:
+                  'Invalid date for ${ifRange ? 'if-range' : 'if-not-modified-since'} header.');
+        }
+      }
+
+      // If-modified didn't work; try etags
+
       if (useEtags == true) {
         var etagsToMatchAgainst = req.headers['if-none-match'];
+        ifRange = false;
+
+        if (etagsToMatchAgainst?.isNotEmpty != true) {
+          etagsToMatchAgainst = req.headers['if-range'];
+          ifRange = etagsToMatchAgainst?.isNotEmpty == true;
+        }
 
         if (etagsToMatchAgainst?.isNotEmpty == true) {
           bool hasBeenModified = false;
@@ -97,38 +147,30 @@ class CachingVirtualDirectory extends VirtualDirectory {
             }
           }
 
-          if (!hasBeenModified) {
+          if (!ifRange) {
-            res.statusCode = 304;
+            if (!hasBeenModified) {
-            setCachedHeaders(stat.modified, req, res);
+              res.statusCode = 304;
-            return new Future.value(false);
+              setCachedHeaders(stat.modified, req, res);
+              return new Future.value(false);
+            }
+          } else {
+            if (!hasBeenModified) {
+              // Continue serving like a regular range...
+              return super.serveFile(file, stat, req, res);
+            } else {
+              // Otherwise, send the whole thing.
+              return res.streamFile(file).then((_) => false);
+            }
           }
         }
       }
 
-      if (req.headers.ifModifiedSince != null) {
-        try {
-          var ifModifiedSince = req.headers.ifModifiedSince;
-
-          if (ifModifiedSince.compareTo(stat.modified) >= 0) {
-            res.statusCode = 304;
-            setCachedHeaders(stat.modified, req, res);
-
-            if (_etags.containsKey(file.absolute.path))
-              res.headers['ETag'] = _etags[file.absolute.path];
-
-            return new Future.value(false);
-          }
-        } catch (_) {
-          throw new AngelHttpException.badRequest(
-              message: 'Invalid date for If-Modified-Since header.');
-        }
-      }
-
       return file.readAsBytes().then((buf) {
-        var etag = _etags[file.absolute.path] = weakEtag(buf);
+        if (useEtags) {
+          res.headers['ETag'] = _etags[file.absolute.path] = md5Etag(buf);
+        }
         //res.statusCode = 200;
         res.headers
-          ..['ETag'] = etag
           ..['content-type'] = res.app.mimeTypeResolver.lookup(file.path) ??
               'application/octet-stream';
         setCachedHeaders(stat.modified, req, res);

lib/src/virtual_directory.dart

@@ -3,6 +3,7 @@ import 'package:angel_framework/angel_framework.dart';
 import 'package:file/file.dart';
 import 'package:http_parser/http_parser.dart';
 import 'package:path/path.dart' as p;
+import 'package:range_header/range_header.dart';
 
 final RegExp _param = new RegExp(r':([A-Za-z0-9_]+)(\((.+)\))?');
 final RegExp _straySlashes = new RegExp(r'(^/+)|(/+$)');
@@ -223,22 +224,108 @@ class VirtualDirectory {
   /// Writes the contents of a file to a response.
   Future<bool> serveFile(
       File file, FileStat stat, RequestContext req, ResponseContext res) async {
-    if (req.method == 'HEAD') return false;
+    if (req.method == 'HEAD') {
+      res.headers['accept-ranges'] = 'bytes';
+      return false;
+    }
 
     if (callback != null) {
-      var r = callback(file, req, res);
+      return await req.app.executeHandler(
-      r = r is Future ? await r : r;
+          (RequestContext req, ResponseContext res) => callback(file, req, res),
-      return r == true;
+          req,
-      //if (r != null && r != true) return r;
+          res);
     }
 
     var type =
         app.mimeTypeResolver.lookup(file.path) ?? 'application/octet-stream';
+    res.headers['accept-ranges'] = 'bytes';
     _ensureContentTypeAllowed(type, req);
+    res.headers['accept-ranges'] = 'bytes';
     res.contentType = new MediaType.parse(type);
-
     if (useBuffer == true) res.useBuffer();
-    await res.streamFile(file);
+
+    if (req.headers.value('range')?.startsWith('bytes ') != true) {
+      await res.streamFile(file);
+    } else {
+      var header = new RangeHeader.parse(req.headers.value('range'));
+      var items = RangeHeader.foldItems(header.items);
+      var totalFileSize = await file.length();
+      header = new RangeHeader(items);
+
+      for (var item in header.items) {
+        bool invalid = false;
+
+        if (item.start != -1) {
+          invalid = item.end != -1 && item.end < item.start;
+        } else
+          invalid = item.end == -1;
+
+        if (invalid) {
+          throw new AngelHttpException(
+              new Exception("Semantically invalid, or unbounded range."),
+              statusCode: 416,
+              message: "Semantically invalid, or unbounded range.");
+        }
+
+        // Ensure it's within range.
+        if (item.start >= totalFileSize || item.end >= totalFileSize) {
+          throw new AngelHttpException(
+              new Exception("Given range $item is out of bounds."),
+              statusCode: 416,
+              message: "Given range $item is out of bounds.");
+        }
+      }
+
+      if (header.items.isEmpty) {
+        throw new AngelHttpException(null,
+            statusCode: 416, message: '`Range` header may not be empty.');
+      } else if (header.items.length == 1) {
+        var item = header.items[0];
+        Stream<List<int>> stream;
+        int len = 0, total = totalFileSize;
+
+        if (item.start == -1) {
+          if (item.end == -1) {
+            len = total;
+            stream = file.openRead();
+          } else {
+            len = item.end + 1;
+            stream = file.openRead(0, item.end + 1);
+          }
+        } else {
+          if (item.end == -1) {
+            len = total - item.start;
+            stream = file.openRead(item.start);
+          } else {
+            len = item.end - item.start + 1;
+            stream = file.openRead(item.start, item.end + 1);
+          }
+        }
+
+        res.contentType = new MediaType.parse(
+            app.mimeTypeResolver.lookup(file.path) ??
+                'application/octet-stream');
+        res.statusCode = 206;
+        res.headers['content-length'] = len.toString();
+        res.headers['content-range'] = 'bytes ' + item.toContentRange(total);
+        await stream.pipe(res);
+        return false;
+      } else {
+        var transformer = new RangeHeaderTransformer(
+            header,
+            app.mimeTypeResolver.lookup(file.path) ??
+                'application/octet-stream',
+            await file.length());
+        res.statusCode = 206;
+        res.headers['content-length'] =
+            transformer.computeContentLength(totalFileSize).toString();
+        res.contentType = new MediaType(
+            'multipart', 'byteranges', {'boundary': transformer.boundary});
+        await file.openRead().transform(transformer).pipe(res);
+        return false;
+      }
+    }
+
     return false;
   }
 }

pubspec.yaml

@@ -1,15 +1,18 @@
 name: angel_static
-description: Static server middleware for Angel. Use this to serve files to users.
+description: Static server middleware for Angel. Also capable of serving Range responses.
 environment:
   sdk: ">=1.8.0 <3.0.0"
 homepage: https://github.com/angel-dart/static
 author: Tobe O <thosakwe@gmail.com>
-version: 2.0.2
+version: 2.1.0
 dependencies:
   angel_framework: ^2.0.0-alpha
+  convert: ^2.0.0
+  crypto: ^2.0.0
   file: ^5.0.0
   http_parser: ^3.0.0
   path: ^1.4.2
+  range_header: ^2.0.0
 dev_dependencies:
   angel_test: ^2.0.0-alpha
   http: