[rhythmbox] podcast: do a HEAD request first before downloading

[Jonathan Matthew <jmatthew src gnome org>]

commit f1b997f33254a7febb1d008b52db0795c34390f6
Author: Jonathan Matthew <jonathan d14n org>
Date:   Sat Sep 26 19:32:25 2020 +1000

    podcast: do a HEAD request first before downloading
    
    This lets us get the file size before we ask for a range from the server,
    so if we have the full file already, we don't get a 'range not satisfiable'
    error.

 podcast/rb-podcast-manager.c | 206 ++++++++++++++++++++++++++-----------------
 1 file changed, 124 insertions(+), 82 deletions(-)
---
diff --git a/podcast/rb-podcast-manager.c b/podcast/rb-podcast-manager.c
index 7e77bec6f..45095c389 100644
--- a/podcast/rb-podcast-manager.c
+++ b/podcast/rb-podcast-manager.c
@@ -1922,6 +1922,28 @@ get_local_download_uri (RBPodcastManager *pd, RBPodcastDownload *download)
        return local_file_uri;
 }
 
+static void
+finish_download (RBPodcastManager *pd, RBPodcastDownload *download, guint64 remote_size, guint64 downloaded)
+{
+       GValue val = {0,};
+
+       rb_debug ("download of %s completed", get_remote_location (download->entry));
+
+       g_value_init (&val, G_TYPE_UINT64);
+       g_value_set_uint64 (&val, downloaded);
+       rhythmdb_entry_set (pd->priv->db, download->entry, RHYTHMDB_PROP_FILE_SIZE, &val);
+       g_value_unset (&val);
+
+       if (remote_size == 0 || downloaded >= remote_size) {
+               g_value_init (&val, G_TYPE_ULONG);
+               g_value_set_ulong (&val, RHYTHMDB_PODCAST_STATUS_COMPLETE);
+               rhythmdb_entry_set (pd->priv->db, download->entry, RHYTHMDB_PROP_STATUS, &val);
+               g_value_unset (&val);
+       }
+
+       rb_podcast_manager_save_metadata (pd, download->entry);
+}
+
 static gboolean
 retry_on_error (GError *error)
 {
@@ -1979,6 +2001,61 @@ download_task (GTask *task, gpointer source_object, gpointer task_data, GCancell
        gboolean retry;
        gboolean eof;
        int retries;
+       GValue val = {0,};
+       char *dl_uri;
+       char *sane_dl_uri;
+
+       /*
+        * first do a HEAD request to get the remote file size and determine the local
+        * file name.
+        */
+       retries = 5;
+       remote_size = 0;
+       while (retries-- > 0) {
+               if (download->in_stream != NULL) {
+                       g_input_stream_close (download->in_stream, NULL, NULL);
+                       g_clear_object (&download->in_stream);
+               }
+               g_clear_object (&download->request);
+               g_clear_error (&error);
+
+               download->request = soup_message_new ("HEAD", get_remote_location (download->entry));
+               download->in_stream = soup_session_send (pd->priv->soup_session, download->request, 
download->cancel, &error);
+               if (error == NULL && !SOUP_STATUS_IS_SUCCESSFUL (download->request->status_code)) {
+                       error = g_error_new (SOUP_HTTP_ERROR, download->request->status_code, "%s", 
download->request->reason_phrase);
+               }
+
+               if (error == NULL) {
+                       remote_size = soup_message_headers_get_content_length 
(download->request->response_headers);
+                       rb_debug ("remote file size %ld", remote_size);
+                       break;
+               } else if (retry_on_error (error) == FALSE) {
+                       rb_debug ("giving up after error from http request: %s", error->message);
+                       g_task_return_error (task, error);
+                       break;
+               }
+
+               rb_debug ("retrying after error from http request: %s", error->message);
+               g_usleep (DOWNLOAD_RETRY_DELAY * G_USEC_PER_SEC);
+       }
+
+       if (error != NULL) {
+               g_task_return_error (task, error);
+               return;
+       }
+
+       dl_uri = get_local_download_uri (pd, download);
+       sane_dl_uri = rb_sanitize_uri_for_filesystem (dl_uri, NULL);
+       g_free (dl_uri);
+
+       rb_debug ("download URI: %s", sane_dl_uri);
+
+       if (rb_uri_create_parent_dirs (sane_dl_uri, &error) == FALSE) {
+               rb_debug ("error creating parent dirs: %s", error->message);
+               g_task_return_error (task, error);
+               g_free (sane_dl_uri);
+               return;
+       }
 
        /*
         * if we already have a local download location, get the file size
@@ -1987,36 +2064,61 @@ download_task (GTask *task, gpointer source_object, gpointer task_data, GCancell
         * to detect changes in the remote file better.
         */
        local_file_uri = get_download_location (download->entry);
+       downloaded = 0;
        if (local_file_uri != NULL) {
-               rb_debug ("checking local copy at %s", local_file_uri);
                download->destination = g_file_new_for_uri (local_file_uri);
-               if (g_file_query_exists (download->destination, NULL)) {
-                       GFileInfo *dest_info;
+               if (strcmp (local_file_uri, sane_dl_uri) == 0) {
+                       rb_debug ("checking local copy at %s", local_file_uri);
+                       if (g_file_query_exists (download->destination, NULL)) {
+                               GFileInfo *dest_info;
+
+                               dest_info = g_file_query_info (download->destination,
+                                                              G_FILE_ATTRIBUTE_STANDARD_SIZE,
+                                                              G_FILE_QUERY_INFO_NONE,
+                                                              NULL,
+                                                              &error);
+                               if (error != NULL) {
+                                       g_task_return_error (task, error);
+                                       g_free (sane_dl_uri);
+                                       return;
+                               }
 
-                       dest_info = g_file_query_info (download->destination,
-                                                      G_FILE_ATTRIBUTE_STANDARD_SIZE,
-                                                      G_FILE_QUERY_INFO_NONE,
-                                                      NULL,
-                                                      &error);
-                       if (error != NULL) {
-                               g_task_return_error (task, error);
-                               return;
+                               downloaded = g_file_info_get_attribute_uint64 (dest_info, 
G_FILE_ATTRIBUTE_STANDARD_SIZE);
+                               g_object_unref (dest_info);
+                       } else {
+                               rb_debug ("local copy not found");
                        }
-
-                       downloaded = g_file_info_get_attribute_uint64 (dest_info, 
G_FILE_ATTRIBUTE_STANDARD_SIZE);
-                       g_object_unref (dest_info);
                } else {
-                       /* clear download location? */
-                       rb_debug ("local copy not found");
-                       downloaded = 0;
+                       rb_debug ("local download uri has changed, removing old file at %s", local_file_uri);
+                       g_file_delete (download->destination, download->cancel, NULL);
+                       download->destination = NULL;
                }
-       } else {
-               rb_debug ("no local copy location set");
+       }
+
+       if (download->destination == NULL) {
+               /* set the download location for the episode */
+               g_value_init (&val, G_TYPE_STRING);
+               g_value_set_string (&val, sane_dl_uri);
+               set_download_location (pd->priv->db, download->entry, &val);
+               g_value_unset (&val);
+
+               rhythmdb_commit (pd->priv->db);
+
+               download->destination = g_file_new_for_uri (sane_dl_uri);
+       }
+       g_free (sane_dl_uri);
+
+       if (downloaded == remote_size) {
+               rb_debug ("local file is the same size as the download (%" G_GUINT64_FORMAT ")",
+                         downloaded);
+               finish_download (pd, download, remote_size, downloaded);
+               g_task_return_boolean (task, TRUE);
+               return;
+       } else if (downloaded > remote_size) {
+               rb_debug ("replacing local file as it's larger than the download");
                downloaded = 0;
        }
 
-       remote_size = -1;
-       retries = 5;
        while (retries-- > 0) {
                if (download->in_stream != NULL) {
                        g_input_stream_close (download->in_stream, NULL, NULL);
@@ -2063,50 +2165,6 @@ download_task (GTask *task, gpointer source_object, gpointer task_data, GCancell
                                remote_size = soup_message_headers_get_content_length 
(download->request->response_headers);
                                rb_debug ("server didn't honour range request, starting again, total %ld", 
remote_size);
                        }
-               } else {
-                       remote_size = soup_message_headers_get_content_length 
(download->request->response_headers);
-                       rb_debug ("total download size %ld", remote_size);
-               }
-
-               if (downloaded == remote_size) {
-                       rb_debug ("local file is the same size as the download (%" G_GUINT64_FORMAT ")",
-                                 downloaded);
-                       break;
-               } else if (downloaded > remote_size) {
-                       rb_debug ("replacing local file as it's larger than the download");
-
-                       downloaded = 0;
-                       continue;
-               }
-
-               if (download->destination == NULL) {
-                       GValue val = {0,};
-                       char *dl_uri;
-                       char *sane_dl_uri;
-
-                       dl_uri = get_local_download_uri (pd, download);
-                       sane_dl_uri = rb_sanitize_uri_for_filesystem (dl_uri, NULL);
-                       g_free (dl_uri);
-
-                       rb_debug ("download URI: %s", sane_dl_uri);
-
-                       if (rb_uri_create_parent_dirs (sane_dl_uri, &error) == FALSE) {
-                               rb_debug ("error creating parent dirs: %s", error->message);
-                               g_task_return_error (task, error);
-                               g_free (sane_dl_uri);
-                               return;
-                       }
-
-                       /* set the download location for the episode */
-                       g_value_init (&val, G_TYPE_STRING);
-                       g_value_set_string (&val, sane_dl_uri);
-                       set_download_location (pd->priv->db, download->entry, &val);
-                       g_value_unset (&val);
-
-                       rhythmdb_commit (pd->priv->db);
-
-                       download->destination = g_file_new_for_uri (sane_dl_uri);
-                       g_free (sane_dl_uri);
                }
 
                /* open the local file */
@@ -2191,23 +2249,7 @@ download_task (GTask *task, gpointer source_object, gpointer task_data, GCancell
        if (error != NULL) {
                g_task_return_error (task, error);
        } else {
-               GValue val = {0,};
-
-               rb_debug ("download of %s completed", get_remote_location (download->entry));
-
-               g_value_init (&val, G_TYPE_UINT64);
-               g_value_set_uint64 (&val, downloaded);
-               rhythmdb_entry_set (pd->priv->db, download->entry, RHYTHMDB_PROP_FILE_SIZE, &val);
-               g_value_unset (&val);
-
-               if (remote_size == 0 || downloaded >= remote_size) {
-                       g_value_init (&val, G_TYPE_ULONG);
-                       g_value_set_ulong (&val, RHYTHMDB_PODCAST_STATUS_COMPLETE);
-                       rhythmdb_entry_set (pd->priv->db, download->entry, RHYTHMDB_PROP_STATUS, &val);
-                       g_value_unset (&val);
-               }
-
-               rb_podcast_manager_save_metadata (pd, download->entry);
+               finish_download (pd, download, remote_size, downloaded);
                g_task_return_boolean (task, TRUE);
        }