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: http://neptun.sai.msu.su/manual/misc/client_block_api.html
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Apache 1.1 and earlier let modules handle POST and PUT
requests by themselves. The module would, on its own, determine
whether the request had an entity, how many bytes it was, and
then called a function (read_client_block
) to get
the data.
However, HTTP/1.1 requires several things of POST and PUT request handlers that did not fit into this module, and all existing modules have to be rewritten. The API calls for handling this have been further abstracted, so that future HTTP protocol changes can be accomplished while remaining backwards-compatible.
int ap_setup_client_block (request_rec *, int read_policy); int ap_should_client_block (request_rec *); long ap_get_client_block (request_rec *, char *buffer, int buffer_size);
ap_setup_client_block()
near the
beginning of the request handler. This will set up all the
necessary properties, and will return either OK, or an
error code. If the latter, the module should return that
error code. The second parameter selects the policy to
apply if the request message indicates a body, and how a
chunked transfer-coding should be interpreted. Choose one
of
REQUEST_NO_BODY Send 413 error if message has any body REQUEST_CHUNKED_ERROR Send 411 error if body without Content-Length REQUEST_CHUNKED_DECHUNK If chunked, remove the chunks for me. REQUEST_CHUNKED_PASS Pass the chunks to me without removal.In order to use the last two options, the caller MUST provide a buffer large enough to hold a chunk-size line, including any extensions.
ap_should_client_block()
. This will tell the
module whether or not to read input. If it is 0, the module
should assume that the input is of a non-entity type
(e.g., a GET request). A nonzero response indicates
that the module should proceed (to step 3). This step also
sends a 100 Continue response to HTTP/1.1 clients, so should
not be called until the module is
*definitely* ready to read content.
(otherwise, the point of the 100 response is defeated). Never
call this function more than once.ap_get_client_block
in a loop.
Pass it a buffer and its size. It will put data into the
buffer (not necessarily the full buffer, in the case of
chunked inputs), and return the length of the input block.
When it is done reading, it will return 0 if EOF, or -1 if
there was an error.As an example, please look at the code in
mod_cgi.c
. This is properly written to the new API
guidelines.