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GNet Network Library Reference Manual | |
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#include <gnet.h>
GConnHttp;
enum GConnHttpMethod;
enum GConnHttpError;
enum GConnHttpEventType;
GConnHttpEvent;
GConnHttpEventResolved;
GConnHttpEventResponse;
GConnHttpEventRedirect;
GConnHttpEventData;
GConnHttpEventError;
void (*GConnHttpFunc) (GConnHttp *conn,
GConnHttpEvent *event,
gpointer user_data);
enum GConnHttpHeaderFlags;
GConnHttp* gnet_conn_http_new (void);
gboolean gnet_conn_http_set_uri (GConnHttp *conn,
const gchar *uri);
gboolean gnet_conn_http_set_escaped_uri (GConnHttp *conn,
const gchar *uri);
gboolean gnet_conn_http_set_header (GConnHttp *conn,
const gchar *field,
const gchar *value,
GConnHttpHeaderFlags flags);
void gnet_conn_http_set_max_redirects (GConnHttp *conn,
guint num);
void gnet_conn_http_set_timeout (GConnHttp *conn,
guint timeout);
gboolean gnet_conn_http_set_user_agent (GConnHttp *conn,
const gchar *agent);
gboolean gnet_conn_http_set_method (GConnHttp *conn,
GConnHttpMethod method,
const gchar *post_data,
gsize post_data_len);
gboolean gnet_conn_http_set_main_context (GConnHttp *conn,
GMainContext *context);
void gnet_conn_http_run_async (GConnHttp *conn,
GConnHttpFunc func,
gpointer user_data);
gboolean gnet_conn_http_run (GConnHttp *conn,
GConnHttpFunc func,
gpointer user_data);
gboolean gnet_conn_http_steal_buffer (GConnHttp *conn,
gchar **buffer,
gsize *length);
void gnet_conn_http_cancel (GConnHttp *conn);
void gnet_conn_http_delete (GConnHttp *conn);
gboolean gnet_http_get (const gchar *url,
gchar **buffer,
gsize *length,
guint *response);
A GConnHttp represents a HTTP client connection. A GConnHttp
is created directly by calling gnet_conn_http_new(). After
that set the URI to retrieve using gnet_conn_http_set_uri().
A connection is made and the HTTP request sent only once
either gnet_conn_http_run_async() or gnet_conn_http_run()
is called. Use the asynchroneous variant if you want the
function to return immediately and prefer to receive data
and status information in the background via the callback
function. gnet_conn_http_run_async() assumes that there is
already a GLib main loop running (e.g. the Gtk main loop).
You can decide for yourself how much information you would like to receive during the HTTP operation. All status information is communicated to the caller via the optional callback function.
The easiest way to just retrieve some data via HTTP is to
use the convenience function gnet_http_get().
Here is a small example how to retrieve a file with the
least amount of effort and error checking (this is
more or less what gnet_http_get() does internally):
Example 1. Simple GConnHttp usage.
#define GNET_EXPERIMENTAL
#include <gnet.h>
void
fetch_and_print_url (const gchar *url)
{
GConnHttp *conn;
conn = gnet_conn_http_new();
gnet_conn_http_set_uri(conn, url);
if (gnet_conn_http_run(conn, NULL, NULL))
{
gchar *buf;
gsize buflen;
if (gnet_conn_http_steal_buffer(conn, &buf, &buflen))
{
g_print ("Received %%u bytes of data:\n%%s\n", buflen, buf);
g_free(buf);
}
}
gnet_conn_http_delete(conn);
}
...
fetch_and_print_url ("http://www.google.com");
...
GConnHttp is still considered less mature than other parts of GNet, even though it should generall work just fine. It just has not received as much testing as other parts of GNet yet. You should not use it in production level code without thoroughly testing it for your purposes. Because of that, you need to define GNET_EXPERIMENTAL in your source code before including the GNet headers (otherwise you will get compiler errors when trying to use it).
typedef struct _GConnHttp GConnHttp;
HTTP Connection. The entire GConnHttp struct is opaque and private.
typedef enum
{
GNET_CONN_HTTP_METHOD_GET,
GNET_CONN_HTTP_METHOD_POST
} GConnHttpMethod;
HTTP request method. Use with gnet_conn_http_set_method().
typedef enum
{
GNET_CONN_HTTP_ERROR_UNSPECIFIED,
GNET_CONN_HTTP_ERROR_PROTOCOL_UNSUPPORTED,
GNET_CONN_HTTP_ERROR_HOSTNAME_RESOLUTION
} GConnHttpError;
Error codes. Used by GConnHttpEventError. Note that errors by the HTTP server will be communicated to the client via the GConnHttpEventResponse event.
typedef enum
{
GNET_CONN_HTTP_RESOLVED, /* resolved host name */
GNET_CONN_HTTP_CONNECTED, /* connected to host */
GNET_CONN_HTTP_RESPONSE, /* got response (incl. headers) */
GNET_CONN_HTTP_REDIRECT, /* got redirect */
GNET_CONN_HTTP_DATA_PARTIAL, /* we got some data */
GNET_CONN_HTTP_DATA_COMPLETE, /* we got all data */
GNET_CONN_HTTP_TIMEOUT, /* the connection timed out */
GNET_CONN_HTTP_ERROR /* GConnHttp problem */
} GConnHttpEventType;
GConnHttp event type.
GNET_CONN_HTTP_RESOLVED |
the host name has been resolved or host name resolution failed. The event structure will be a GConnHttpEventResolved structure |
GNET_CONN_HTTP_CONNECTED |
the TCP connection to the HTTP server has been established |
GNET_CONN_HTTP_RESPONSE |
the HTTP server has sent a response and response headers. The event structure will be a GConnHttpEventResponse structure |
GNET_CONN_HTTP_REDIRECT |
the HTTP server has sent a redirect response. The event structure will be a GConnHttpEventRedirect structure |
GNET_CONN_HTTP_DATA_PARTIAL |
data has been received.
The buffer is caller-owned (ie. owned by GNet), but
may be emptied using gnet_conn_http_steal_buffer(). The
event structure will be a GConnHttpEventData structure
|
GNET_CONN_HTTP_DATA_COMPLETE |
data has been received
in full. The buffer is caller-owned (ie. owned by GNet),
but may be emptied using gnet_conn_http_steal_buffer(). The
event structure will be a GConnHttpEventData structure
|
GNET_CONN_HTTP_TIMEOUT |
the connection timed out |
GNET_CONN_HTTP_ERROR |
GConnHttp problem (not a server error response). The event structure will be a GConnHttpEventError structure |
typedef struct {
GConnHttpEventType type; /* type of event (see above) */
} GConnHttpEvent;
GConnHttp Base Event. Check event->type and then cast the event structure into the corresponding specialised event structure.
GConnHttpEventType type; |
event type |
typedef struct {
GInetAddr *ia; /* GInetAddr of the host name */
} GConnHttpEventResolved;
GConnHttp Host Name Resolved Event. Emitted when the host name has
been resolved to an IP address, primarily to give progress feedback
to the user. ia will be NULL if the host name could not be resolved.
typedef struct {
guint response_code; /* response code, e.g. 200, or 404 */
gchar **header_fields; /* NULL-terminated array of strings */
gchar **header_values; /* NULL-terminated array of strings */
} GConnHttpEventResponse;
Emitted when the server has sent a response and response headers.
guint response_code; |
response code from the HTTP server (e.g. 200 or 404) |
gchar **header_fields; |
array of header field strings, NULL-terminated |
gchar **header_values; |
array of header value strings, NULL-terminated |
typedef struct {
guint num_redirects; /* number of redirects so far */
guint max_redirects; /* max. num. of redirects allowed */
gchar *new_location; /* redirect location if provided */
gboolean auto_redirect; /* FALSE if action is needed */
} GConnHttpEventRedirect;
Emitted when the server sends a redirect response.
guint num_redirects; |
number of redirects so far |
guint max_redirects; |
maximum number of redirects allowed |
gchar *new_location; |
redirect location, or NULL if not provided |
gboolean auto_redirect; |
FALSE if action by the client is needed. Set to FALSE to prevent automatic redirection |
typedef struct {
guint64 content_length; /* set if available, otherwise 0 */
guint64 data_received; /* bytes received so far */
const gchar *buffer; /* buffer */
gsize buffer_length; /* buffer length */
} GConnHttpEventData;
Emitted when data has been received. Useful for progress feedback to the user or to process data before all of it has been received. The client is responsible for emptying the buffer regularly when the amount of data received or expected is larger than the amount that should be kept in memory (e.g. in the case of large binary files).
guint64 content_length; |
set if available, otherwise 0 |
guint64 data_received; |
total amount of data received so far |
const gchar *buffer; |
buffer with data received so far. Use
gnet_conn_http_steal_buffer() to empty the buffer.
|
gsize buffer_length; |
buffer length |
typedef struct {
GConnHttpError code; /* error code */
gchar *message; /* message (use for debugging only) */
} GConnHttpEventError;
Emitted when an error has occured. Note that HTTP server errors are communicated to the client by means of a GConnHttpEventResponse event.
GConnHttpError code; |
one of the GConnHttpError codes |
gchar *message; |
clear-text error message (for debugging purposes only) |
void (*GConnHttpFunc) (GConnHttp *conn, GConnHttpEvent *event, gpointer user_data);
Callback for GConnHttp.
Check event->type and then cast the event into the appropriate event structure. event->type will be one of
GNET_CONN_HTTP_RESOLVED: this event occurs when the host name
has been resolved or host name resolution failed
GNET_CONN_HTTP_CONNECTED: the TCP connection to the
HTTP server has been established
GNET_CONN_HTTP_RESPONSE: the HTTP server has sent a response
and response headers
GNET_CONN_HTTP_REDIRECT: the HTTP server has sent a redirect
response
GNET_CONN_HTTP_DATA_PARTIAL: data has been read. The buffer is
owned by GNet and you must not modify it or free it. You can
take ownership of the buffer with gnet_conn_http_steal_buffer()
GNET_CONN_HTTP_DATA_COMPLETE: data has been received in full.
The buffer is owned by GNet and you must not modify it or free
it. You can acquire ownership of the buffer by calling
gnet_conn_http_steal_buffer()
GNET_CONN_HTTP_TIMEOUT: the connection timed out
GNET_CONN_HTTP_ERROR: GConnHttp problem (not a server error response)
conn : |
GConnHttp |
event : |
event (caller-owned, do not free) |
user_data : |
user data specified in gnet_conn_http_run()
or gnet_conn_http_run_async()
|
typedef enum
{
GNET_CONN_HTTP_FLAG_SKIP_HEADER_CHECK = 1
} GConnHttpHeaderFlags;
Flags for gnet_conn_http_set_header().
GConnHttp* gnet_conn_http_new (void);
Creates a GConnHttp.
| Returns : | a GConnHttp. |
gboolean gnet_conn_http_set_uri (GConnHttp *conn, const gchar *uri);
Sets the URI to GET or POST, e.g. http://www.foo.com/bar.html. uri is
assumed to be unescaped, so all special URI characters will be escaped.
conn : |
a GConnHttp |
uri : |
URI string |
| Returns : | TRUE if the URI has been accepted. |
gboolean gnet_conn_http_set_escaped_uri (GConnHttp *conn, const gchar *uri);
Sets the URI to GET or POST, e.g. http://www.foo.com/My%20Documents/bar.txt
conn : |
a GConnHttp |
uri : |
URI string with special characters already escaped |
| Returns : | TRUE if the URI has been accepted. |
gboolean gnet_conn_http_set_header (GConnHttp *conn, const gchar *field, const gchar *value, GConnHttpHeaderFlags flags);
Set header field to send with the HTTP request.
conn : |
a GConnHttp |
field : |
a header field, e.g. "Accept" |
value : |
the header field value, e.g. "text/html" |
flags : |
one or more flags of GConnHttpHeaderFlags, or 0 |
| Returns : | TRUE if the header field has been set or changed |
void gnet_conn_http_set_max_redirects (GConnHttp *conn, guint num);
Sets the maximum allowed number of automatic redirects. Note that the HTTP protocol specification (RFC2616) specifies occasions where the client must not redirect automatically without user intervention. In those cases, no automatic redirect will be performed, even if the limit has not been reached yet.
conn : |
a GConnHttp |
num : |
the maximum number of allowed automatic redirects |
void gnet_conn_http_set_timeout (GConnHttp *conn, guint timeout);
Sets a timeout on the http connection.
conn : |
a GConnHttp |
timeout : |
timeout in milliseconds |
gboolean gnet_conn_http_set_user_agent (GConnHttp *conn, const gchar *agent);
Convenience function. Wraps gnet_conn_http_set_header().
conn : |
a GConnHttp |
agent : |
the user agent string to send (will be supplemented by a GNet version number comment) |
| Returns : | TRUE if the user agent string has been changed. |
gboolean gnet_conn_http_set_method (GConnHttp *conn, GConnHttpMethod method, const gchar *post_data, gsize post_data_len);
Sets the HTTP request method. Default is the GET method.
conn : |
a GConnHttp |
method : |
a GConnHttpMethod |
post_data : |
post data to send with POST method, or NULL |
post_data_len : |
the length of the post data to send with POST method, or 0 |
| Returns : | TRUE if the method has been changed successfully. |
gboolean gnet_conn_http_set_main_context (GConnHttp *conn, GMainContext *context);
Sets the GLib GMainContext to use for asynchronous operations. You should
call this function right after you create conn. You must not call this
function after the actual connection process has started.
You are very unlikely to ever need this function.
conn : |
a GConnHttp |
context : |
a GMainContext, or NULL to use the default GLib main context |
| Returns : | TRUE on success, FALSE on failure. |
Since 2.0.8
void gnet_conn_http_run_async (GConnHttp *conn, GConnHttpFunc func, gpointer user_data);
Starts connecting and sending the specified http request. Will return immediately. Assumes there is an existing and running default Gtk/GLib/Gnome main loop.
conn : |
a GConnHttp |
func : |
callback function to communicate progress and errors, or NULL |
user_data : |
user data to pass to callback function, or NULL |
gboolean gnet_conn_http_run (GConnHttp *conn, GConnHttpFunc func, gpointer user_data);
Starts connecting and sending the specified http request. Will return once the operation has finished and either an error has occured, or the data has been received in full.
This function will run its own main loop in the default GLib main context
(or the user-specified main context, if one was specified with
gnet_conn_http_set_main_context()), which means that if your application
is based on Gtk+ or sets up GLib timeouts or idle callbacks, it is
possible that those callback functions are invoked while you are waiting
for gnet_conn_http_run() to return. This means you shouldn't make
assumptions about any state you set up before calling this function,
because it might have been changed again from within a callback in the
mean time (if this can happen or not depends on your callbacks and what
they do of course).
conn : |
a GConnHttp |
func : |
callback function to communicate progress and errors, or NULL |
user_data : |
user data to pass to callback function, or NULL |
| Returns : | TRUE if no error occured before connecting |
gboolean gnet_conn_http_steal_buffer (GConnHttp *conn, gchar **buffer, gsize *length);
Empties the current buffer and returns the contents. The
main purpose of this function is to make it possible to
just use gnet_conn_http_run(), check its return value, and
then get the buffer data without having to install a
callback function. Also needed to empty the buffer regularly
while receiving large amounts of data.
The caller (you) needs to free the buffer with g_free() when done.
conn : |
a GConnHttp |
buffer : |
where to store a pointer to the buffer data |
length : |
where to store the length of the buffer data |
| Returns : | TRUE if buffer and length have been set |
void gnet_conn_http_cancel (GConnHttp *conn);
Cancels the current http transfer (if any) and makes
gnet_conn_http_run() return immediately. Will do nothing
if the transfer was started with gnet_conn_http_run_async().
conn : |
a GConnHttp |
void gnet_conn_http_delete (GConnHttp *conn);
Deletes a GConnHttp and frees all associated resources.
conn : |
a GConnHttp |
gboolean gnet_http_get (const gchar *url,
gchar **buffer,
gsize *length,
guint *response);
Convenience function that just retrieves
the provided URI without the need to
set up a full GConnHttp. Uses
gnet_conn_http_run() internally.
Caller (you) needs to free the buffer with g_free() when
no longer needed.
This function will run its own main loop in the default GLib main context,
which means that if your application is based on Gtk+ or sets up GLib
timeouts or idle callbacks, it is possible that those callback functions
are invoked while you are waiting for gnet_http_get() to return. This
means you shouldn't make assumptions about any state you set up before
calling this function, because it might have been changed again from
within a callback in the mean time (if this can happen or not depends on
your callbacks and what they do of course).
url : |
a URI, e.g. http://www.foo.com |
buffer : |
where to store a pointer to the data retrieved |
length : |
where to store the length of the data retrieved |
response : |
where to store the last HTTP response code received from the HTTP server, or NULL. |
| Returns : | TRUE if buffer, length and response are set,
otherwise FALSE.
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