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GResolver provides cancellable synchronous and asynchronous DNS
resolution, for hostnames (g_resolver_lookup_by_address()
,
g_resolver_lookup_by_name()
and their async variants) and SRV
(service) records (g_resolver_lookup_service()
).
GNetworkAddress and GNetworkService provide wrappers around GResolver functionality that also implement GSocketConnectable, making it easy to connect to a remote host/service.
GResolver *
g_resolver_get_default (void
);
Gets the default GResolver. You should unref it when you are done with it. GResolver may use its reference count as a hint about how many threads it should allocate for concurrent DNS resolutions.
Since: 2.22
void
g_resolver_set_default (GResolver *resolver
);
Sets resolver
to be the application's default resolver (reffing
resolver
, and unreffing the previous default resolver, if any).
Future calls to g_resolver_get_default()
will return this resolver.
This can be used if an application wants to perform any sort of DNS caching or "pinning"; it can implement its own GResolver that calls the original default resolver for DNS operations, and implements its own cache policies on top of that, and then set itself as the default resolver for all later code to use.
Since: 2.22
GList * g_resolver_lookup_by_name (GResolver *resolver
,const gchar *hostname
,GCancellable *cancellable
,GError **error
);
Synchronously resolves hostname
to determine its associated IP
address(es). hostname
may be an ASCII-only or UTF-8 hostname, or
the textual form of an IP address (in which case this just becomes
a wrapper around g_inet_address_new_from_string()
).
On success, g_resolver_lookup_by_name()
will return a non-empty GList of
GInetAddress, sorted in order of preference and guaranteed to not
contain duplicates. That is, if using the result to connect to
hostname
, you should attempt to connect to the first address
first, then the second if the first fails, etc. If you are using
the result to listen on a socket, it is appropriate to add each
result using e.g. g_socket_listener_add_address()
.
If the DNS resolution fails, error
(if non-NULL
) will be set to a
value from GResolverError and NULL
will be returned.
If cancellable
is non-NULL
, it can be used to cancel the
operation, in which case error
(if non-NULL
) will be set to
G_IO_ERROR_CANCELLED
.
If you are planning to connect to a socket on the resolved IP address, it may be easier to create a GNetworkAddress and use its GSocketConnectable interface.
resolver |
||
hostname |
the hostname to look up |
|
cancellable |
a GCancellable, or |
[nullable] |
error |
a non-empty GList
of GInetAddress, or NULL
on error. You
must unref each of the addresses and free the list when you are
done with it. (You can use g_resolver_free_addresses()
to do this.).
[element-type GInetAddress][transfer full]
Since: 2.22
void g_resolver_lookup_by_name_async (GResolver *resolver
,const gchar *hostname
,GCancellable *cancellable
,GAsyncReadyCallback callback
,gpointer user_data
);
Begins asynchronously resolving hostname
to determine its
associated IP address(es), and eventually calls callback
, which
must call g_resolver_lookup_by_name_finish()
to get the result.
See g_resolver_lookup_by_name()
for more details.
resolver |
||
hostname |
the hostname to look up the address of |
|
cancellable |
a GCancellable, or |
[nullable] |
callback |
callback to call after resolution completes. |
[scope async] |
user_data |
data for |
[closure] |
Since: 2.22
GList * g_resolver_lookup_by_name_finish (GResolver *resolver
,GAsyncResult *result
,GError **error
);
Retrieves the result of a call to
g_resolver_lookup_by_name_async()
.
If the DNS resolution failed, error
(if non-NULL
) will be set to
a value from GResolverError. If the operation was cancelled,
error
will be set to G_IO_ERROR_CANCELLED
.
a GList
of GInetAddress, or NULL
on error. See g_resolver_lookup_by_name()
for more details.
[element-type GInetAddress][transfer full]
Since: 2.22
void
g_resolver_free_addresses (GList *addresses
);
Frees addresses
(which should be the return value from
g_resolver_lookup_by_name()
or g_resolver_lookup_by_name_finish()
).
(This is a convenience method; you can also simply free the results
by hand.)
[skip]
Since: 2.22
gchar * g_resolver_lookup_by_address (GResolver *resolver
,GInetAddress *address
,GCancellable *cancellable
,GError **error
);
Synchronously reverse-resolves address
to determine its
associated hostname.
If the DNS resolution fails, error
(if non-NULL
) will be set to
a value from GResolverError.
If cancellable
is non-NULL
, it can be used to cancel the
operation, in which case error
(if non-NULL
) will be set to
G_IO_ERROR_CANCELLED
.
resolver |
||
address |
the address to reverse-resolve |
|
cancellable |
a GCancellable, or |
[nullable] |
error |
Since: 2.22
void g_resolver_lookup_by_address_async (GResolver *resolver
,GInetAddress *address
,GCancellable *cancellable
,GAsyncReadyCallback callback
,gpointer user_data
);
Begins asynchronously reverse-resolving address
to determine its
associated hostname, and eventually calls callback
, which must
call g_resolver_lookup_by_address_finish()
to get the final result.
resolver |
||
address |
the address to reverse-resolve |
|
cancellable |
a GCancellable, or |
[nullable] |
callback |
callback to call after resolution completes. |
[scope async] |
user_data |
data for |
[closure] |
Since: 2.22
gchar * g_resolver_lookup_by_address_finish (GResolver *resolver
,GAsyncResult *result
,GError **error
);
Retrieves the result of a previous call to
g_resolver_lookup_by_address_async()
.
If the DNS resolution failed, error
(if non-NULL
) will be set to
a value from GResolverError. If the operation was cancelled,
error
will be set to G_IO_ERROR_CANCELLED
.
Since: 2.22
GList * g_resolver_lookup_service (GResolver *resolver
,const gchar *service
,const gchar *protocol
,const gchar *domain
,GCancellable *cancellable
,GError **error
);
Synchronously performs a DNS SRV lookup for the given service
and
protocol
in the given domain
and returns an array of GSrvTarget.
domain
may be an ASCII-only or UTF-8 hostname. Note also that the
service
and protocol
arguments do not include the leading underscore
that appears in the actual DNS entry.
On success, g_resolver_lookup_service()
will return a non-empty GList of
GSrvTarget, sorted in order of preference. (That is, you should
attempt to connect to the first target first, then the second if
the first fails, etc.)
If the DNS resolution fails, error
(if non-NULL
) will be set to
a value from GResolverError and NULL
will be returned.
If cancellable
is non-NULL
, it can be used to cancel the
operation, in which case error
(if non-NULL
) will be set to
G_IO_ERROR_CANCELLED
.
If you are planning to connect to the service, it is usually easier to create a GNetworkService and use its GSocketConnectable interface.
resolver |
||
service |
the service type to look up (eg, "ldap") |
|
protocol |
the networking protocol to use for |
|
domain |
the DNS domain to look up the service in |
|
cancellable |
a GCancellable, or |
[nullable] |
error |
a non-empty GList of
GSrvTarget, or NULL
on error. You must free each of the targets and the
list when you are done with it. (You can use g_resolver_free_targets()
to do
this.).
[element-type GSrvTarget][transfer full]
Since: 2.22
void g_resolver_lookup_service_async (GResolver *resolver
,const gchar *service
,const gchar *protocol
,const gchar *domain
,GCancellable *cancellable
,GAsyncReadyCallback callback
,gpointer user_data
);
Begins asynchronously performing a DNS SRV lookup for the given
service
and protocol
in the given domain
, and eventually calls
callback
, which must call g_resolver_lookup_service_finish()
to
get the final result. See g_resolver_lookup_service()
for more
details.
resolver |
||
service |
the service type to look up (eg, "ldap") |
|
protocol |
the networking protocol to use for |
|
domain |
the DNS domain to look up the service in |
|
cancellable |
a GCancellable, or |
[nullable] |
callback |
callback to call after resolution completes. |
[scope async] |
user_data |
data for |
[closure] |
Since: 2.22
GList * g_resolver_lookup_service_finish (GResolver *resolver
,GAsyncResult *result
,GError **error
);
Retrieves the result of a previous call to
g_resolver_lookup_service_async()
.
If the DNS resolution failed, error
(if non-NULL
) will be set to
a value from GResolverError. If the operation was cancelled,
error
will be set to G_IO_ERROR_CANCELLED
.
a non-empty GList of
GSrvTarget, or NULL
on error. See g_resolver_lookup_service()
for more
details.
[element-type GSrvTarget][transfer full]
Since: 2.22
void
g_resolver_free_targets (GList *targets
);
Frees targets
(which should be the return value from
g_resolver_lookup_service()
or g_resolver_lookup_service_finish()
).
(This is a convenience method; you can also simply free the
results by hand.)
[skip]
Since: 2.22
GList * g_resolver_lookup_records (GResolver *resolver
,const gchar *rrname
,GResolverRecordType record_type
,GCancellable *cancellable
,GError **error
);
Synchronously performs a DNS record lookup for the given rrname
and returns
a list of records as GVariant tuples. See GResolverRecordType for
information on what the records contain for each record_type
.
If the DNS resolution fails, error
(if non-NULL
) will be set to
a value from GResolverError and NULL
will be returned.
If cancellable
is non-NULL
, it can be used to cancel the
operation, in which case error
(if non-NULL
) will be set to
G_IO_ERROR_CANCELLED
.
resolver |
||
rrname |
the DNS name to lookup the record for |
|
record_type |
the type of DNS record to lookup |
|
cancellable |
a GCancellable, or |
[nullable] |
error |
a non-empty GList of
GVariant, or NULL
on error. You must free each of the records and the list
when you are done with it. (You can use g_list_free_full()
with
g_variant_unref()
to do this.).
[element-type GVariant][transfer full]
Since: 2.34
void g_resolver_lookup_records_async (GResolver *resolver
,const gchar *rrname
,GResolverRecordType record_type
,GCancellable *cancellable
,GAsyncReadyCallback callback
,gpointer user_data
);
Begins asynchronously performing a DNS lookup for the given
rrname
, and eventually calls callback
, which must call
g_resolver_lookup_records_finish()
to get the final result. See
g_resolver_lookup_records()
for more details.
resolver |
||
rrname |
the DNS name to lookup the record for |
|
record_type |
the type of DNS record to lookup |
|
cancellable |
a GCancellable, or |
[nullable] |
callback |
callback to call after resolution completes. |
[scope async] |
user_data |
data for |
[closure] |
Since: 2.34
GList * g_resolver_lookup_records_finish (GResolver *resolver
,GAsyncResult *result
,GError **error
);
Retrieves the result of a previous call to
g_resolver_lookup_records_async()
. Returns a non-empty list of records as
GVariant tuples. See GResolverRecordType for information on what the
records contain.
If the DNS resolution failed, error
(if non-NULL
) will be set to
a value from GResolverError. If the operation was cancelled,
error
will be set to G_IO_ERROR_CANCELLED
.
a non-empty GList of
GVariant, or NULL
on error. You must free each of the records and the list
when you are done with it. (You can use g_list_free_full()
with
g_variant_unref()
to do this.).
[element-type GVariant][transfer full]
Since: 2.34
typedef struct _GResolver GResolver;
The object that handles DNS resolution. Use g_resolver_get_default()
to get the default resolver.
This is an abstract type; subclasses of it implement different resolvers for different platforms and situations.
The type of record that g_resolver_lookup_records()
or
g_resolver_lookup_records_async()
should retrieve. The records are returned
as lists of GVariant tuples. Each record type has different values in
the variant tuples returned.
G_RESOLVER_RECORD_SRV
records are returned as variants with the signature
'(qqqs)', containing a guint16 with the priority, a guint16 with the
weight, a guint16 with the port, and a string of the hostname.
G_RESOLVER_RECORD_MX
records are returned as variants with the signature
'(qs)', representing a guint16 with the preference, and a string containing
the mail exchanger hostname.
G_RESOLVER_RECORD_TXT
records are returned as variants with the signature
'(as)', representing an array of the strings in the text record.
G_RESOLVER_RECORD_SOA
records are returned as variants with the signature
'(ssuuuuu)', representing a string containing the primary name server, a
string containing the administrator, the serial as a guint32, the refresh
interval as guint32, the retry interval as a guint32, the expire timeout
as a guint32, and the ttl as a guint32.
G_RESOLVER_RECORD_NS
records are returned as variants with the signature
'(s)', representing a string of the hostname of the name server.
Since: 2.34
#define G_RESOLVER_ERROR (g_resolver_error_quark ())
Error domain for GResolver. Errors in this domain will be from the GResolverError enumeration. See GError for more information on error domains.
An error code used with G_RESOLVER_ERROR
in a GError returned
from a GResolver routine.
Since: 2.22