[geocode-glib] geocode-nominatim: Add a user-agent property to override the User-Agent

[Philip Withnall <pwithnall src gnome org>]

commit d229c5983f22c7f1bb37149cadde6b520cffc249
Author: Philip Withnall <philip withnall collabora co uk>
Date:   Thu Oct 13 18:52:58 2016 +0100

    geocode-nominatim: Add a user-agent property to override the User-Agent
    
    If an application wants to set a custom User-Agent, they can now do so
    via this property. This is probably sufficiently rarely needed that it
    can remain as a property of GeocodeNominatim, without a getter or
    setter, and without being exposed on GeocodeForward and GeocodeReverse.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=756313

 geocode-glib/geocode-glib-private.h |    2 +-
 geocode-glib/geocode-glib.c         |   21 ++++++++------
 geocode-glib/geocode-nominatim.c    |   50 ++++++++++++++++++++++++++++++++---
 3 files changed, 59 insertions(+), 14 deletions(-)
---
diff --git a/geocode-glib/geocode-glib-private.h b/geocode-glib/geocode-glib-private.h
index 6af8fea..8dbdb68 100644
--- a/geocode-glib/geocode-glib-private.h
+++ b/geocode-glib/geocode-glib-private.h
@@ -50,7 +50,7 @@ gboolean _geocode_glib_cache_load (SoupMessage *query,
                                    char       **contents);
 GHashTable *_geocode_glib_dup_hash_table (GHashTable *ht);
 gboolean _geocode_object_is_number_after_street (void);
-SoupSession *_geocode_glib_build_soup_session (void);
+SoupSession *_geocode_glib_build_soup_session (const gchar *user_agent_override);
 
 G_END_DECLS
 
diff --git a/geocode-glib/geocode-glib.c b/geocode-glib/geocode-glib.c
index 6215fd1..2496484 100644
--- a/geocode-glib/geocode-glib.c
+++ b/geocode-glib/geocode-glib.c
@@ -38,26 +38,29 @@
  **/
 
 SoupSession *
-_geocode_glib_build_soup_session (void)
+_geocode_glib_build_soup_session (const gchar *user_agent_override)
 {
-       GApplication *application;
-       SoupSession *session;
        char *user_agent;
+       g_autofree gchar *user_agent_allocated = NULL;
 
-       application = g_application_get_default ();
-       if (application) {
+       if (user_agent_override != NULL) {
+               user_agent = user_agent_override;
+       } else if (g_application_get_default () != NULL) {
+               GApplication *application = g_application_get_default ();
                const char *id = g_application_get_application_id (application);
                user_agent = g_strdup_printf ("geocode-glib/%s (%s)",
                                              PACKAGE_VERSION, id);
+               user_agent_allocated = user_agent;
        } else {
                user_agent = g_strdup_printf ("geocode-glib/%s",
                                              PACKAGE_VERSION);
+               user_agent_allocated = user_agent;
        }
 
-       session = soup_session_new_with_options (SOUP_SESSION_USER_AGENT,
-                                                user_agent, NULL);
-       g_free (user_agent);
-       return session;
+       g_debug ("%s: user_agent = %s", G_STRFUNC, user_agent);
+
+       return soup_session_new_with_options (SOUP_SESSION_USER_AGENT,
+                                             user_agent, NULL);
 }
 
 char *
diff --git a/geocode-glib/geocode-nominatim.c b/geocode-glib/geocode-nominatim.c
index 5da11c4..2b86eb2 100644
--- a/geocode-glib/geocode-nominatim.c
+++ b/geocode-glib/geocode-nominatim.c
@@ -35,13 +35,15 @@
 typedef enum {
        PROP_BASE_URL = 1,
        PROP_MAINTAINER_EMAIL_ADDRESS,
+       PROP_USER_AGENT,
 } GeocodeNominatimProperty;
 
-static GParamSpec *properties[PROP_MAINTAINER_EMAIL_ADDRESS + 1];
+static GParamSpec *properties[PROP_USER_AGENT + 1];
 
 typedef struct {
        char *base_url;
        char *maintainer_email_address;
+       char *user_agent;
 } GeocodeNominatimPrivate;
 
 static void geocode_backend_iface_init (GeocodeBackendInterface *iface);
@@ -877,9 +879,14 @@ on_cache_data_loaded (GFile        *cache,
                       GAsyncResult *res,
                       GTask        *task)
 {
+       GeocodeNominatim *self;
+       GeocodeNominatimPrivate *priv;
        char *contents;
        SoupSession *soup_session;
 
+       self = g_task_get_source_object (task);
+       priv = geocode_nominatim_get_instance_private (self);
+
        if (g_file_load_contents_finish (cache,
                                         res,
                                         &contents,
@@ -891,7 +898,7 @@ on_cache_data_loaded (GFile        *cache,
                return;
        }
 
-       soup_session = _geocode_glib_build_soup_session ();
+       soup_session = _geocode_glib_build_soup_session (priv->user_agent);
        soup_session_queue_message (soup_session,
                                    g_object_ref (g_task_get_task_data (task)),
                                    (SoupSessionCallback) on_query_data_loaded,
@@ -932,7 +939,7 @@ geocode_nominatim_query_async (GeocodeNominatim    *self,
                return;
        }
 
-       soup_session = _geocode_glib_build_soup_session ();
+       soup_session = _geocode_glib_build_soup_session (priv->user_agent);
        soup_session_queue_message (soup_session,
                                    g_object_ref (soup_query),
                                    (SoupSessionCallback) on_query_data_loaded,
@@ -955,7 +962,7 @@ geocode_nominatim_query (GeocodeNominatim  *self,
        if (g_cancellable_set_error_if_cancelled (cancellable, error))
                return NULL;
 
-       soup_session = _geocode_glib_build_soup_session ();
+       soup_session = _geocode_glib_build_soup_session (priv->user_agent);
        soup_query = soup_message_new (SOUP_METHOD_GET, uri);
 
        if (_geocode_glib_cache_load (soup_query, &contents) == FALSE) {
@@ -1353,6 +1360,9 @@ geocode_nominatim_get_property (GObject    *object,
        case PROP_MAINTAINER_EMAIL_ADDRESS:
                g_value_set_string (value, priv->maintainer_email_address);
                break;
+       case PROP_USER_AGENT:
+               g_value_set_string (value, priv->user_agent);
+               break;
        default:
                /* We don't have any other property... */
                G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
@@ -1381,6 +1391,14 @@ geocode_nominatim_set_property (GObject      *object,
                g_assert (priv->maintainer_email_address == NULL);
                priv->maintainer_email_address = g_value_dup_string (value);
                break;
+       case PROP_USER_AGENT:
+               if (g_strcmp0 (priv->user_agent, g_value_get_string (value)) != 0) {
+                       g_free (priv->user_agent);
+                       priv->user_agent = g_value_dup_string (value);
+                       g_object_notify_by_pspec (object,
+                                                 properties[PROP_USER_AGENT]);
+               }
+               break;
        default:
                /* We don't have any other property... */
                G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
@@ -1397,6 +1415,7 @@ geocode_nominatim_finalize (GObject *object)
 
        g_free (priv->base_url);
        g_free (priv->maintainer_email_address);
+       g_free (priv->user_agent);
 
        G_OBJECT_CLASS (geocode_nominatim_parent_class)->finalize (object);
 }
@@ -1462,6 +1481,29 @@ geocode_nominatim_class_init (GeocodeNominatimClass *klass)
                                  G_PARAM_CONSTRUCT_ONLY |
                                  G_PARAM_STATIC_STRINGS));
 
+       /**
+        * GeocodeNominatim:user-agent:
+        *
+        * User-Agent string to send with HTTP(S) requests, or %NULL to use the
+        * default user agent, which is derived from the geocode-glib version
+        * and #GApplication:id, for example: `geocode-glib/3.20 (MyAppId)`.
+        *
+        * As per the
+        * [Nominatim usage policy](http://wiki.openstreetmap.org/wiki/Nominatim_usage_policy),
+        * it should be set to a string which identifies the application which
+        * is using geocode-glib, and must be a valid
+        * [user agent](https://tools.ietf.org/html/rfc7231#section-5.5.3)
+        * string.
+        *
+        * Since: UNRELEASED
+        */
+       properties[PROP_USER_AGENT] = g_param_spec_string ("user-agent",
+                                                          "User agent",
+                                                          "User-Agent string to send with HTTP(S) requests",
+                                                          NULL,
+                                                          (G_PARAM_READWRITE |
+                                                           G_PARAM_STATIC_STRINGS));
+
        g_object_class_install_properties (object_class,
                                           G_N_ELEMENTS (properties), properties);
 }