[gnome-online-accounts/wip/rishi/owncloud-gssapi: 3/7] httpclient: Add API to detect supported authentication mechanisms

[Debarshi Ray <debarshir src gnome org>]

commit ce26bfd28c45bd4019984045031d2c214b89e14a
Author: Debarshi Ray <debarshir gnome org>
Date:   Sat Feb 20 19:53:03 2016 +0100

    httpclient: Add API to detect supported authentication mechanisms
    
    Given a URI, goa_http_client_detect will try to find out if the system
    already has the required credentials (eg., Kerberos ticket) to log into
    the server. In case the necessary credentials are missing, it will
    return the value of the WWW-Authenticate header as a comma-separated
    list.
    
    We will use this to determine what kind of credentials the user needs
    to provide when creating an account.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=762097

 src/goabackend/goahttpclient.c |  150 ++++++++++++++++++++++++++++++++++++++++
 src/goabackend/goahttpclient.h |   10 +++-
 2 files changed, 159 insertions(+), 1 deletions(-)
---
diff --git a/src/goabackend/goahttpclient.c b/src/goabackend/goahttpclient.c
index bdc9d4c..75f6749 100644
--- a/src/goabackend/goahttpclient.c
+++ b/src/goabackend/goahttpclient.c
@@ -18,6 +18,7 @@
 
 #include "config.h"
 
+#include <glib/gi18n-lib.h>
 #include <libsoup/soup.h>
 
 #include "goahttpclient.h"
@@ -342,3 +343,152 @@ goa_http_client_check_sync (GoaHttpClient       *self,
 
   return data.op_res;
 }
+
+/* ---------------------------------------------------------------------------------------------------- */
+
+typedef struct
+{
+  GCancellable *cancellable;
+  GSimpleAsyncResult *res;
+  SoupMessage *msg;
+  SoupSession *session;
+  gulong cancellable_id;
+} DetectData;
+
+static gboolean
+http_client_detect_data_free (gpointer user_data)
+{
+  DetectData *data = user_data;
+
+  g_simple_async_result_complete_in_idle (data->res);
+
+  g_cancellable_disconnect (data->cancellable, data->cancellable_id);
+  g_clear_object (&data->cancellable);
+
+  /* soup_session_queue_message stole the references to data->msg */
+  g_object_unref (data->res);
+  g_object_unref (data->session);
+  g_slice_free (DetectData, data);
+
+  return G_SOURCE_REMOVE;
+}
+
+static void
+http_client_detect_cancelled_cb (GCancellable *cancellable, gpointer user_data)
+{
+  DetectData *data = user_data;
+  soup_session_abort (data->session);
+}
+
+static void
+http_client_detect_response_cb (SoupSession *session, SoupMessage *msg, gpointer user_data)
+{
+  GError *error = NULL;
+  DetectData *data = user_data;
+  GMainContext *context;
+  GSource *source;
+
+  /* status == SOUP_STATUS_CANCELLED, if we are being aborted by the
+   * GCancellable.
+   */
+  if (msg->status_code == SOUP_STATUS_CANCELLED)
+    goto out;
+  else if (msg->status_code == SOUP_STATUS_SSL_FAILED)
+    {
+      g_set_error_literal (&error, GOA_ERROR, GOA_ERROR_SSL, _("Invalid certificate."));
+      goto out;
+    }
+  else if (msg->status_code != SOUP_STATUS_OK && msg->status_code != SOUP_STATUS_UNAUTHORIZED)
+    {
+      g_warning ("goa_http_client_detect() failed: %u — %s", msg->status_code, msg->reason_phrase);
+      goa_utils_set_error_soup (&error, msg);
+      goto out;
+    }
+
+  if (msg->status_code == SOUP_STATUS_UNAUTHORIZED)
+    {
+      const gchar *value;
+
+      value = soup_message_headers_get_list (msg->response_headers, "WWW-Authenticate");
+      g_simple_async_result_set_op_res_gpointer (data->res, g_strdup (value), g_free);
+    }
+
+ out:
+  /* error == NULL, if we are being aborted by the GCancellable.
+   */
+  if (error != NULL)
+    g_simple_async_result_take_error (data->res, error);
+
+  source = g_idle_source_new ();
+  g_source_set_priority (source, G_PRIORITY_DEFAULT_IDLE);
+  g_source_set_callback (source, http_client_detect_data_free, data, NULL);
+  g_source_set_name (source, "[goa] http_client_detect_data_free");
+
+  context = g_main_context_get_thread_default ();
+  g_source_attach (source, context);
+  g_source_unref (source);
+}
+
+void
+goa_http_client_detect (GoaHttpClient       *self,
+                        const gchar         *uri,
+                        GCancellable        *cancellable,
+                        GAsyncReadyCallback  callback,
+                        gpointer             user_data)
+{
+  DetectData *data;
+  SoupLogger *logger;
+
+  g_return_if_fail (GOA_IS_HTTP_CLIENT (self));
+  g_return_if_fail (uri != NULL && uri[0] != '\0');
+  g_return_if_fail (cancellable == NULL || G_IS_CANCELLABLE (cancellable));
+
+  data = g_slice_new0 (DetectData);
+  data->res = g_simple_async_result_new (G_OBJECT (self), callback, user_data, goa_http_client_detect);
+  data->session = soup_session_new ();
+
+  if (soup_auth_negotiate_supported)
+    {
+      soup_session_add_feature_by_type (data->session, SOUP_TYPE_AUTH_NEGOTIATE);
+      soup_session_add_feature_by_type (data->session, SOUP_TYPE_COOKIE_JAR);
+    }
+
+  logger = soup_logger_new (SOUP_LOGGER_LOG_BODY, -1);
+  soup_logger_set_printer (logger, http_client_log_printer, NULL, NULL);
+  soup_session_add_feature (data->session, SOUP_SESSION_FEATURE (logger));
+  g_object_unref (logger);
+
+  data->msg = soup_message_new (SOUP_METHOD_GET, uri);
+
+  if (cancellable != NULL)
+    {
+      data->cancellable = g_object_ref (cancellable);
+      data->cancellable_id = g_cancellable_connect (data->cancellable,
+                                                    G_CALLBACK (http_client_detect_cancelled_cb),
+                                                    data,
+                                                    NULL);
+      g_simple_async_result_set_check_cancellable (data->res, data->cancellable);
+    }
+
+  soup_session_queue_message (data->session, data->msg, http_client_detect_response_cb, data);
+}
+
+gchar *
+goa_http_client_detect_finish (GoaHttpClient *self, GAsyncResult *res, GError **error)
+{
+  GSimpleAsyncResult *simple;
+  gchar *ret = NULL;
+
+  g_return_val_if_fail (g_simple_async_result_is_valid (res, G_OBJECT (self), goa_http_client_detect), 
FALSE);
+  g_return_val_if_fail (error == NULL || *error == NULL, FALSE);
+
+  simple = G_SIMPLE_ASYNC_RESULT (res);
+
+  if (g_simple_async_result_propagate_error (simple, error))
+    goto out;
+
+  ret = g_strdup (g_simple_async_result_get_op_res_gpointer (simple));
+
+ out:
+  return ret;
+}
diff --git a/src/goabackend/goahttpclient.h b/src/goabackend/goahttpclient.h
index 676b183..fe54698 100644
--- a/src/goabackend/goahttpclient.h
+++ b/src/goabackend/goahttpclient.h
@@ -1,6 +1,6 @@
 /* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
 /*
- * Copyright (C) 2012, 2013, 2015 Red Hat, Inc.
+ * Copyright (C) 2012, 2013, 2015, 2016 Red Hat, Inc.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
@@ -55,6 +55,14 @@ gboolean        goa_http_client_check_sync         (GoaHttpClient       *self,
                                                     gboolean             accept_ssl_errors,
                                                     GCancellable        *cancellable,
                                                     GError             **error);
+void            goa_http_client_detect             (GoaHttpClient       *self,
+                                                    const gchar         *uri,
+                                                    GCancellable        *cancellable,
+                                                    GAsyncReadyCallback  callback,
+                                                    gpointer             user_data);
+gchar          *goa_http_client_detect_finish      (GoaHttpClient       *self,
+                                                    GAsyncResult        *res,
+                                                    GError             **error);
 
 G_END_DECLS