Chunk video files to bypass throttling

src/invidious.cr

@@ -54,6 +54,7 @@ MAX_ITEMS_PER_PAGE = 1500
 
 REQUEST_HEADERS_WHITELIST  = {"Accept", "Accept-Encoding", "Cache-Control", "Connection", "Content-Length", "If-None-Match", "Range"}
 RESPONSE_HEADERS_BLACKLIST = {"Access-Control-Allow-Origin", "Alt-Svc", "Server"}
+HTTP_CHUNK_SIZE            = 10485760 # ~10MB
 
 CURRENT_BRANCH  = {{ "#{`git branch | sed -n '/\* /s///p'`.strip}" }}
 CURRENT_COMMIT  = {{ "#{`git rev-list HEAD --max-count=1 --abbrev-commit`.strip}" }}
@@ -4640,31 +4641,58 @@ get "/videoplayback" do |env|
     next
   end
 
+  content_length = nil
+  first_chunk = true
+  range_start, range_end = parse_range(env.request.headers["Range"]?)
+  chunk_start = range_start
+  chunk_end = range_end
+
+  if !chunk_end || chunk_end - chunk_start > HTTP_CHUNK_SIZE
+    chunk_end = chunk_start + HTTP_CHUNK_SIZE - 1
+  end
+
+  while true
+    if !range_end && content_length
+      range_end = content_length
+    end
+
+    if range_end && chunk_start > range_end
+      break
+    end
+
+    if range_end && chunk_end > range_end
+      chunk_end = range_end
+    end
+
+    headers["Range"] = "bytes=#{chunk_start}-#{chunk_end}"
     client = make_client(URI.parse(host), region)
     begin
       client.get(url, headers) do |response|
+        if first_chunk
+          if !env.request.headers["Range"]? && response.status_code == 206
+            env.response.status_code = 200
+          else
             env.response.status_code = response.status_code
+          end
 
           response.headers.each do |key, value|
-        if !RESPONSE_HEADERS_BLACKLIST.includes? key
+            if !RESPONSE_HEADERS_BLACKLIST.includes?(key) && key != "Content-Range"
               env.response.headers[key] = value
             end
           end
 
           env.response.headers["Access-Control-Allow-Origin"] = "*"
 
-      if response.headers["Location"]?
-        url = URI.parse(response.headers["Location"])
-        host = url.host
-
-        url = url.full_path
-        url += "&host=#{host}"
+          if location = response.headers["Location"]?
+            location = URI.parse(location)
+            location = "#{location.full_path}&host=#{location.host}"
 
             if region
-          url += "&region=#{region}"
+              location += "&region=#{region}"
             end
 
-        next env.redirect url
+            env.redirect location
+            break
           end
 
           if title = query_params["title"]?
@@ -4672,9 +4700,26 @@ get "/videoplayback" do |env|
             env.response.headers["Content-Disposition"] = "attachment; filename=\"#{URI.escape(title)}\"; filename*=UTF-8''#{URI.escape(title)}"
           end
 
+          content_length = response.headers["Content-Range"].split("/")[-1].to_i64
+          if env.request.headers["Range"]?
+            env.response.headers["Content-Range"] = "bytes #{range_start}-#{range_end || (content_length - 1)}/#{content_length}"
+            env.response.content_length = ((range_end.try &.+ 1) || content_length) - range_start
+          else
+            env.response.content_length = content_length
+          end
+        end
+
         proxy_file(response, env)
       end
     rescue ex
+      if ex.message != "Error reading socket: Connection reset by peer"
+        break
+      end
+    end
+
+    chunk_start = chunk_end + 1
+    chunk_end += HTTP_CHUNK_SIZE
+    first_chunk = false
   end
 end
 

src/invidious/helpers/utils.cr

@@ -347,3 +347,21 @@ def subscribe_pubsub(topic, key, config)
 
   return client.post("/subscribe", form: body)
 end
+
+def parse_range(range)
+  if !range
+    return 0_i64, nil
+  end
+
+  ranges = range.lchop("bytes=").split(',')
+  ranges.each do |range|
+    start_range, end_range = range.split('-')
+
+    start_range = start_range.to_i64? || 0_i64
+    end_range = end_range.to_i64?
+
+    return start_range, end_range
+  end
+
+  return 0_i64, nil
+end