URL_Fetcher Protocol module interface

URL_Fetcher

» Protocol module interface

Protocol module interface

The protocol module SWI interface is only called by the URL module. URL module clients should never call the ReadData/Status/GetData/Stop SWIs directly. The protocol modules are required to supply a SWI interface. There are currently 4 SWIs that need to be supported which run from SWI_base to SWI_base+3. New SWIs common to all protocol modules will only be added at the low end of the SWI range. Protocol modules must generate standard SWI not known error (error number &1E6) if they receive a call which they do not understand, so that the URL module can determine that they do not support the SWI. Note that there is no general requirement to use SWIs from offset 0 into a SWI chunk, although it makes sense to do this. Protocol modules which support multiple protocols should ensure that they do not place their internal “SWI bases” less than 16 SWIs apart to allow space to future expansion. e.g. AcornHTTP registers http: as &83F80 and https: as &83F90.

Protocol-specific SWIs should be added at the top end of the SWI chunk (ie start at SWI_base+63 and work down) – the AcornHTTP module uses that range to provide clients with access to its HTTP cookie management code, for example.

Note

The session identifiers used by the URL module to talk to the protocol modules are not the same identifiers used by clients to talk to the URL module. They are not interchangeable.

SWI interface

• Protocol_GetData
• Protocol_Status
• Protocol_ReadData
• Protocol_Stop