nsIProtocolProxyService

IID:e38ab577-786e-4a7f-936b-7ae4c7d877b2
Inherits From:nsISupports
Status:UNDER_REVIEW

nsIProtocolProxyService provides methods to access information about various network proxies.

This interface is intended to be used as a service. To create an object implementing this interface:

var obj = Components.classes["@mozilla.org/network/protocol-proxy-service;1"].
            getService(Components.interfaces.nsIProtocolProxyService);

This interface is implemented by the following components:


Constants

This flag may be passed to the resolve method to request that it fail instead of block the calling thread. Proxy Auto Config (PAC) may perform a synchronous DNS query, which may not return immediately. So, calling resolve without this flag may result in locking up the calling thread for a lengthy period of time.

By passing this flag to resolve, one can failover to asyncResolve to avoid locking up the calling thread if a PAC query is required.

When this flag is passed to resolve, resolve may throw the exception NS_BASE_STREAM_WOULD_BLOCK to indicate that it failed due to this flag being present.

PRUint32 RESOLVE_NON_BLOCKING = 1

Methods

nsICancelable asyncResolve ( nsIURI URI , PRUint32 flags , nsIProtocolProxyCallback callback ) nsIProxyInfo getFailoverForProxy ( nsIProxyInfo proxyInfo , nsIURI URI , nsresult reason ) nsIProxyInfo newProxyInfo ( ACString type , AUTF8String host , PRInt32 port , PRUint32 flags , PRUint32 failoverTimeout , nsIProxyInfo failoverProxy ) void registerFilter ( nsIProtocolProxyFilter filter , PRUint32 position ) nsIProxyInfo resolve ( nsIURI URI , PRUint32 flags ) void unregisterFilter ( nsIProtocolProxyFilter filter )

nsICancelable asyncResolve ( nsIURI URI , PRUint32 flags , nsIProtocolProxyCallback callback )

This method is an asychronous version of the resolve method. Unlike resolve, this method is guaranteed not to block the calling thread waiting for DNS queries to complete. This method is intended as a substitute for resolve when the result is not needed immediately.

Arguments:
URI: The URI to test.
flags: A bit-wise OR of the RESOLVE_ flags defined above. Pass 0 to specify the default behavior.
callback: The object to be notified when the result is available.
Returns:
An object that can be used to cancel the asychronous operation.

nsIProxyInfo getFailoverForProxy ( nsIProxyInfo proxyInfo , nsIURI URI , nsresult reason )

If the proxy identified by proxyInfo is unavailable for some reason, this method may be called to access an alternate proxy that may be used instead. As a side-effect, this method may affect future result values from resolve/asyncResolve as well as from getFailoverForProxy.

Arguments:
proxyInfo: The proxy that was unavailable.
URI: The URI that was originally passed to resolve/asyncResolve.
reason: The error code corresponding to the proxy failure. This value may be used to tune the delay before this proxy is used again.

nsIProxyInfo newProxyInfo ( ACString type , AUTF8String host , PRInt32 port , PRUint32 flags , PRUint32 failoverTimeout , nsIProxyInfo failoverProxy )

This method may be called to construct a nsIProxyInfo instance from the given parameters. This method may be useful in conjunction with nsISocketTransportService::createTransport for creating, for example, a SOCKS connection.

Arguments:
type: The proxy type. This is a string value that identifies the proxy type. Standard values include: "http" - specifies a HTTP proxy "socks" - specifies a SOCKS version 5 proxy "socks4" - specifies a SOCKS version 4 proxy "direct" - specifies a direct connection (useful for failover) The type name is case-insensitive. Other string values may be possible.
host: The proxy hostname or IP address.
port: The proxy port.
flags: Flags associated with this connection. See nsIProxyInfo.idl for currently defined flags.
failoverTimeout: Specifies the length of time (in seconds) to ignore this proxy if this proxy fails. Pass PR_UINT32_MAX to specify the default timeout value, causing nsIProxyInfo::failoverTimeout to be assigned the default value.
failoverProxy: Specifies the next proxy to try if this proxy fails. This parameter may be null.

void registerFilter ( nsIProtocolProxyFilter filter , PRUint32 position )

This method may be used to register a proxy filter instance. Each proxy filter is registered with an associated position that determines the order in which the filters are applied (starting from position 0). When resolve/asyncResolve is called, it generates a list of proxies for the given URI, and then it applies the proxy filters. The filters have the opportunity to modify the list of proxies.

If two filters register for the same position, then the filters will be visited in the order in which they were registered.

If the filter is already registered, then its position will be updated.

After filters have been run, any disabled or disallowed proxies will be removed from the list. A proxy is disabled if it had previously failed- over to another proxy (see getFailoverForProxy). A proxy is disallowed, for example, if it is a HTTP proxy and the nsIProtocolHandler for the queried URI does not permit proxying via HTTP.

If a nsIProtocolHandler disallows all proxying, then filters will never have a chance to intercept proxy requests for such URLs.

NOTE: It is possible to construct filters that compete with one another in undesirable ways. This API does not attempt to protect against such problems. It is recommended that any extensions that choose to call this method make their position value configurable at runtime (perhaps via the preferences service).

Arguments:
filter: The nsIProtocolProxyFilter instance to be registered.
position: The position of the filter.

nsIProxyInfo resolve ( nsIURI URI , PRUint32 flags )

This method returns a nsIProxyInfo instance that identifies a proxy to be used for loading the given URI. Otherwise, this method returns null indicating that a direct connection should be used.

NOTE: If this proxy is unavailable, getFailoverForProxy may be called to determine the correct secondary proxy to be used.

NOTE: If the protocol handler for the given URI supports nsIProxiedProtocolHandler, then the nsIProxyInfo instance returned from resolve may be passed to the newProxiedChannel method to create a nsIChannel to the given URI that uses the specified proxy.

NOTE: However, if the nsIProxyInfo type is "http", then it means that the given URI should be loaded using the HTTP protocol handler, which also supports nsIProxiedProtocolHandler.

NOTE: If PAC is configured, and the PAC file has not yet been loaded, then this method will return a nsIProxyInfo instance with a type of "unknown" to indicate to the consumer that asyncResolve should be used to wait for the PAC file to finish loading. Otherwise, the consumer may choose to treat the result as type "direct" if desired.

Arguments:
URI: The URI to test.
flags: A bit-wise OR of the RESOLVE_ flags defined above. Pass 0 to specify the default behavior.

void unregisterFilter ( nsIProtocolProxyFilter filter )

This method may be used to unregister a proxy filter instance. All filters will be automatically unregistered at XPCOM shutdown.

Arguments:
filter: The nsIProtocolProxyFilter instance to be unregistered.

References

This interface is passed as an argument to the following methods:

nsIProtocolProxyFilter.applyFilter

Reference documentation is generated from Mozilla's source.

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