Bug 1918194 - Part 1: Add background task extras to nsIIncrementalDownload MAR GETs. r=bytesized,bhearsum,necko-reviewers,application-update-reviewers,csadilek,jesup

This adds extra headers and query parameters to identify MAR GET
requests as originating from browsing profiles or background task
profiles.

This extracts a simple existing function for setting headers and then
makes it available to `nsIIncrementalDownload`.  The existing function
is not the most pleasant API, but it exists and is much easier than
working through the details of storing header name-value pairs until
they are ready to be used.  It's also the same API exposed by Windows
BITS, so there's no additional manipulation required to support BITS.

Differential Revision: https://phabricator.services.mozilla.com/D221860

dom/webbrowserpersist/nsWebBrowserPersist.cpp

@@ -1410,31 +1410,11 @@ nsresult nsWebBrowserPersist::SaveURIInternal(
 
     // Headers
     if (aExtraHeaders) {
-      nsAutoCString oneHeader;
-      nsAutoCString headerName;
-      nsAutoCString headerValue;
-      int32_t crlf = 0;
-      int32_t colon = 0;
-      const char* kWhitespace = "\b\t\r\n ";
-      nsAutoCString extraHeaders(aExtraHeaders);
-      while (true) {
-        crlf = extraHeaders.Find("\r\n");
-        if (crlf == -1) break;
-        extraHeaders.Mid(oneHeader, 0, crlf);
-        extraHeaders.Cut(0, crlf + 2);
-        colon = oneHeader.Find(":");
-        if (colon == -1) break;  // Should have a colon
-        oneHeader.Left(headerName, colon);
-        colon++;
-        oneHeader.Mid(headerValue, colon, oneHeader.Length() - colon);
-        headerName.Trim(kWhitespace);
-        headerValue.Trim(kWhitespace);
-        // Add the header (merging if required)
-        rv = httpChannel->SetRequestHeader(headerName, headerValue, true);
-        if (NS_FAILED(rv)) {
-          EndDownload(NS_ERROR_FAILURE);
-          return NS_ERROR_FAILURE;
-        }
+      rv = mozilla::net::AddExtraHeaders(httpChannel,
+                                         nsDependentCString(aExtraHeaders));
+      if (NS_FAILED(rv)) {
+        EndDownload(NS_ERROR_FAILURE);
+        return NS_ERROR_FAILURE;
       }
     }
   }

netwerk/base/nsIIncrementalDownload.idl

@@ -49,9 +49,10 @@ interface nsIIncrementalDownload : nsIRequest
    *        The amount of time to wait between fetching chunks.  Pass a
    *        negative to use the default interval, or 0 to fetch the remaining
    *        part of the file in one chunk.
+   * @param extraHeaders Additional headers to supply with the HTTP request.
    */
   void init(in nsIURI uri, in nsIFile destination, in long chunkSize,
-            in long intervalInSeconds);
+            in long intervalInSeconds, in ACString extraHeaders);
 
   /**
    * The URI being fetched.

netwerk/base/nsIncrementalDownload.cpp

@@ -149,6 +149,7 @@ class nsIncrementalDownload final : public nsIIncrementalDownload,
   nsCOMPtr<nsIChannel> mNewRedirectChannel;
   nsCString mPartialValidator;
   bool mCacheBust{false};
+  nsCString mExtraHeaders;
 
   // nsITimerCallback is implemented on a subclass so that the name attribute
   // doesn't conflict with the name attribute of the nsIRequest interface.
@@ -248,6 +249,11 @@ nsresult nsIncrementalDownload::ProcessTimeout() {
   rv = ClearRequestHeader(http);
   if (NS_FAILED(rv)) return rv;
 
+  if (!mExtraHeaders.IsEmpty()) {
+    rv = AddExtraHeaders(http, mExtraHeaders);
+    if (NS_FAILED(rv)) return rv;
+  }
+
   // Don't bother making a range request if we are just going to fetch the
   // entire document.
   if (mInterval || mCurrentSize != int64_t(0)) {
@@ -416,7 +422,7 @@ nsIncrementalDownload::SetLoadGroup(nsILoadGroup* loadGroup) {
 
 NS_IMETHODIMP
 nsIncrementalDownload::Init(nsIURI* uri, nsIFile* dest, int32_t chunkSize,
-                            int32_t interval) {
+                            int32_t interval, const nsACString& extraHeaders) {
   // Keep it simple: only allow initialization once
   NS_ENSURE_FALSE(mURI, NS_ERROR_ALREADY_INITIALIZED);
 
@@ -428,6 +434,9 @@ nsIncrementalDownload::Init(nsIURI* uri, nsIFile* dest, int32_t chunkSize,
 
   if (chunkSize > 0) mChunkSize = chunkSize;
   if (interval >= 0) mInterval = interval;
+
+  mExtraHeaders = extraHeaders;
+
   return NS_OK;
 }
 
@@ -843,6 +852,11 @@ nsIncrementalDownload::AsyncOnChannelRedirect(
   nsresult rv = ClearRequestHeader(newHttpChannel);
   if (NS_FAILED(rv)) return rv;
 
+  if (!mExtraHeaders.IsEmpty()) {
+    rv = AddExtraHeaders(http, mExtraHeaders);
+    if (NS_FAILED(rv)) return rv;
+  }
+
   // If we didn't have a Range header, then we must be doing a full download.
   nsAutoCString rangeVal;
   Unused << http->GetRequestHeader(rangeHdr, rangeVal);

netwerk/base/nsNetUtil.cpp

@@ -4126,5 +4126,35 @@ bool IsCoepCredentiallessEnabled(bool aIsOriginTrialCoepCredentiallessEnabled) {
          aIsOriginTrialCoepCredentiallessEnabled;
 }
 
+nsresult AddExtraHeaders(nsIHttpChannel* aHttpChannel,
+                         const nsACString& aExtraHeaders,
+                         bool aMerge /* = true */) {
+  nsresult rv;
+  nsAutoCString oneHeader;
+  nsAutoCString headerName;
+  nsAutoCString headerValue;
+  int32_t crlf = 0;
+  int32_t colon = 0;
+  const char* kWhitespace = "\b\t\r\n ";
+  nsAutoCString extraHeaders(aExtraHeaders);
+  while (true) {
+    crlf = extraHeaders.Find("\r\n");
+    if (crlf == -1) break;
+    extraHeaders.Mid(oneHeader, 0, crlf);
+    extraHeaders.Cut(0, crlf + 2);
+    colon = oneHeader.Find(":");
+    if (colon == -1) break;  // Should have a colon.
+    oneHeader.Left(headerName, colon);
+    colon++;
+    oneHeader.Mid(headerValue, colon, oneHeader.Length() - colon);
+    headerName.Trim(kWhitespace);
+    headerValue.Trim(kWhitespace);
+    // Add the header (merging if required).
+    rv = aHttpChannel->SetRequestHeader(headerName, headerValue, aMerge);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+  return NS_OK;
+}
+
 }  // namespace net
 }  // namespace mozilla

netwerk/base/nsNetUtil.h

@@ -1188,6 +1188,10 @@ void CheckForBrokenChromeURL(nsILoadInfo* aLoadInfo, nsIURI* aURI);
 
 bool IsCoepCredentiallessEnabled(bool aIsOriginTrialCoepCredentiallessEnabled);
 
+void ParseSimpleURISchemes(const nsACString& schemeList);
+
+nsresult AddExtraHeaders(nsIHttpChannel* aHttpChannel,
+                         const nsACString& aExtraHeaders, bool aMerge = true);
 }  // namespace net
 }  // namespace mozilla
 

toolkit/mozapps/update/UpdateService.sys.mjs

@@ -6142,6 +6142,63 @@ class Downloader {
     );
   }
 
+  /**
+   * Given a patch URL, return a URL possibly modified with extra query
+   * parameters and extra headers.  The extras help identify whether this update
+   * is driven by a regular browsing Firefox or by a background update task.
+   *
+   * @param {string} [patchURL] Unmodified patch URL.
+   * @return { url, extraHeaders }
+   */
+  _maybeWithExtras(patchURL) {
+    let shouldAddExtras = true;
+    if (AppConstants.MOZ_APP_NAME !== "firefox") {
+      shouldAddExtras = false;
+    }
+    if (Services.policies) {
+      let policies = Services.policies.getActivePolicies();
+      if (policies) {
+        if ("AppUpdateURL" in policies) {
+          shouldAddExtras = false;
+        }
+      }
+    }
+
+    if (!shouldAddExtras) {
+      LOG("Downloader:_maybeWithExtras - Not adding extras");
+      return { url: patchURL, extraHeaders: "\r\n" };
+    }
+
+    LOG("Downloader:_maybeWithExtras - Adding extras");
+
+    let modeStr = lazy.gIsBackgroundTaskMode ? "1" : "0";
+    let extraHeaders = `X-BackgroundTaskMode: ${modeStr}\r\n`;
+    let extraParameters = [["backgroundTaskMode", modeStr]];
+
+    if (lazy.gIsBackgroundTaskMode) {
+      const bts = Cc["@mozilla.org/backgroundtasks;1"].getService(
+        Ci.nsIBackgroundTasks
+      );
+      extraHeaders += `X-BackgroundTaskName: ${bts.backgroundTaskName()}\r\n`;
+      extraParameters.push(["backgroundTaskName", bts.backgroundTaskName()]);
+    }
+
+    extraHeaders += "\r\n";
+
+    let url = patchURL;
+    let parsedUrl = URL.parse(url);
+    if (parsedUrl) {
+      for (let [p, v] of extraParameters) {
+        parsedUrl.searchParams.set(p, v);
+      }
+      url = parsedUrl.href;
+    } else {
+      LOG("Downloader:_maybeWithExtras - Failed to parse patch URL!");
+    }
+
+    return { url, extraHeaders };
+  }
+
   /**
    * Download and stage the given update.
    * @param   update
@@ -6196,6 +6253,12 @@ class Downloader {
       canUseBits = this._canUseBits(this._patch);
     }
 
+    // When using Firefox and Mozilla's update server, add extra headers and
+    // extra query parameters identifying whether this request is on behalf of a
+    // regular browsing profile (0) or a background task (1).  This helps
+    // understand bandwidth usage of background updates in production.
+    let { url, extraHeaders } = this._maybeWithExtras(this._patch.URL);
+
     if (!canUseBits) {
       this._pendingRequest = null;
 
@@ -6247,18 +6310,25 @@ class Downloader {
       LOG(
         "Downloader:downloadUpdate - Starting nsIIncrementalDownload with " +
           "url: " +
-          this._patch.URL +
+          url +
           ", path: " +
           patchFile.path +
           ", interval: " +
           interval
       );
-      let uri = Services.io.newURI(this._patch.URL);
+      let uri = Services.io.newURI(url);
 
       this._request = Cc[
         "@mozilla.org/network/incremental-download;1"
       ].createInstance(Ci.nsIIncrementalDownload);
-      this._request.init(uri, patchFile, DOWNLOAD_CHUNK_SIZE, interval);
+
+      this._request.init(
+        uri,
+        patchFile,
+        DOWNLOAD_CHUNK_SIZE,
+        interval,
+        extraHeaders
+      );
       this._request.start(this, null);
     } else {
       this._bitsActiveNotifications = this.hasDownloadListeners;