[PATCH 01/18] flickr: Add helper function to get a frob

["Juan A. Suarez Romero" <jasuarez igalia com>]

Flickr requires that users grants permissions to access to Flickr account. So
client applications should shown a message to grant this access in order to
plugin to access Flickr's content.

This function helps client developers in a first step: getting a valid frob.
---
 src/flickr/Makefile.am       |   19 +++++++-
 src/flickr/grl-flickr-auth.c |   89 ++++++++++++++++++++++++++++++++++++++++++
 src/flickr/grl-flickr-auth.h |   32 +++++++++++++++
 3 files changed, 137 insertions(+), 3 deletions(-)
 create mode 100644 src/flickr/grl-flickr-auth.c
 create mode 100644 src/flickr/grl-flickr-auth.h

diff --git a/src/flickr/Makefile.am b/src/flickr/Makefile.am
index 41e19e8..a0a099b 100644
--- a/src/flickr/Makefile.am
+++ b/src/flickr/Makefile.am
@@ -5,7 +5,9 @@
 #
 # Copyright (C) 2010 Igalia S.L. All rights reserved.
 
-lib_LTLIBRARIES		 = libgrlflickr.la
+libplugin_LTLIBRARIES	= libgrlflickr.la
+
+libauth_LTLIBRARIES	= libgrlflickrauth.la
 
 libgrlflickr_la_CFLAGS =	\
 	$(DEPS_CFLAGS)		\
@@ -23,9 +25,20 @@ libgrlflickr_la_SOURCES =	\
 	gflickr.c		\
 	gflickr.h
 
-libdir=$(GRL_PLUGINS_DIR)
+libgrlflickrauth_la_CFLAGS =	\
+	$(libgrlflickr_la_CFLAGS)
+
+libgrlflickrauth_la_LIBADD =	\
+	$(libgrlflickr_la_LIBADD)
+
+libgrlflickrauth_la_SOURCES =	\
+	grl-flickr-auth.c	\
+	grl-flickr-auth.h
+
+libplugindir=$(GRL_PLUGINS_DIR)
+libauthdir=$(libdir)
 
-flickrlibxmldir		= $(libdir)
+flickrlibxmldir		= $(libplugindir)
 flickrlibxml_DATA	= libgrlflickr.xml
 
 EXTRA_DIR = $(flickrlibdata_DATA)
diff --git a/src/flickr/grl-flickr-auth.c b/src/flickr/grl-flickr-auth.c
new file mode 100644
index 0000000..fee3f83
--- /dev/null
+++ b/src/flickr/grl-flickr-auth.c
@@ -0,0 +1,89 @@
+#include "grl-flickr-auth.h"
+
+#include <gio/gio.h>
+#include <libxml/parser.h>
+#include <libxml/xpath.h>
+
+#define FLICKR_ENTRYPOINT "http://api.flickr.com/services/rest/?";
+
+gchar *
+grl_flickr_get_frob (const gchar *api_key,
+                     const gchar *secret)
+{
+  gchar *to_sign;
+  gchar *api_sig;
+  gchar *url;
+  GVfs *vfs;
+  GFile *uri;
+  gchar *contents;
+  xmlDocPtr xmldoc = NULL;
+  xmlXPathContextPtr xpath_ctx = NULL;
+  xmlXPathObjectPtr xpath_res = NULL;
+  GError *error = NULL;
+  gchar *frob = NULL;
+
+  /* Get api sig */
+  to_sign = g_strdup_printf ("%s"
+                             "api_key%s"
+                             "method" "flickr.auth.getFrob",
+                             secret,
+                             api_key);
+  api_sig = g_compute_checksum_for_string (G_CHECKSUM_MD5, to_sign, -1);
+  g_free (to_sign);
+
+  /* Build url */
+  url = g_strdup_printf (FLICKR_ENTRYPOINT
+                         "method=flickr.auth.getFrob&"
+                         "api_key=%s&"
+                         "api_sig=%s",
+                         api_key,
+                         api_sig);
+  g_free (api_sig);
+
+  /* Load content */
+  vfs = g_vfs_get_default ();
+  uri = g_vfs_get_file_for_uri (vfs, url);
+  g_free (url);
+  if (!g_file_load_contents (uri, NULL, &contents, NULL, NULL, &error)) {
+    g_warning ("Unable to get Flickr's frob: %s", error->message);
+    return NULL;
+  }
+
+  /* Get frob */
+  xmldoc = xmlReadMemory (contents, xmlStrlen ((xmlChar *)contents), NULL, NULL,
+                          XML_PARSE_RECOVER | XML_PARSE_NOBLANKS);
+  g_free (contents);
+
+  if (xmldoc) {
+    xpath_ctx = xmlXPathNewContext (xmldoc);
+    if (xpath_ctx) {
+      xpath_res = xmlXPathEvalExpression ((xmlChar *) "/rsp/frob", xpath_ctx);
+      if (xpath_res && xpath_res->nodesetval->nodeTab) {
+        frob = (gchar *) xmlNodeListGetString (xmldoc,
+                                               xpath_res->nodesetval->nodeTab[0]->xmlChildrenNode,
+                                               1);
+      } else {
+        g_warning ("Flick's frob not found");
+      }
+    } else {
+      g_warning ("Unable to create Flickr's XPath");
+    }
+  } else {
+    g_warning ("Unable to parse Flickr XML reply");
+  }
+
+  /* Free data */
+  if (xmldoc) {
+    xmlFreeDoc (xmldoc);
+  }
+
+  if (xpath_ctx) {
+    xmlXPathFreeContext (xpath_ctx);
+  }
+
+  if (xpath_res) {
+    xmlXPathFreeObject (xpath_res);
+  }
+
+  return frob;
+}
diff --git a/src/flickr/grl-flickr-auth.h b/src/flickr/grl-flickr-auth.h
new file mode 100644
index 0000000..8ec238b
--- /dev/null
+++ b/src/flickr/grl-flickr-auth.h
@@ -0,0 +1,32 @@
+/*
+ * Copyright (C) 2010 Igalia S.L.
+ *
+ * Contact: Iago Toral Quiroga <itoral igalia com>
+ *
+ * Authors: Juan A. Suarez Romero <jasuarez igalia com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public License
+ * as published by the Free Software Foundation; version 2.1 of
+ * the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA
+ *
+ */
+
+#ifndef _GRL_FLICKR_AUTH_SOURCE_H_
+#define _GRL_FLICKR_AUTH_SOURCE_H_
+
+#include <glib.h>
+
+gchar * grl_flickr_get_frob (const gchar *api_key,
+                             const gchar *secret);
+#endif /* _GRL_FLICKR_AUTH_SOURCE_H_ */
-- 
1.7.0.4