use http_chunk_append_file_ref() and http_chunk_append_file_ref_range()
reduce resource usage (number of fds open) by reference counting open
fds to files served, and sharing the fd among FILE_CHUNKs in responses
defer optimization to read small files into memory until after
response_start hooks have a chance to run, e.g. until after
mod_deflate chooses whether or not to serve file from compressed
cache, if deflate.cache-dir is configured
translate config server.modules "mod_compress" to "mod_deflate"
accept compress.* directives, but issue DEPRECATED warning trace
mod_deflate differences from mod_compress:
- mod_compress compress.filetype was exact match; deflate.mimetypes is
prefix match (behavior change might compress longer mimetype matches,
which are likely of similar type and compressability)
- mod_compress always sent entire (compressed) file for Range request
mod_deflate will stream compress range result (not stored in cache)
- mod_compress would short-circuit request with 403 Forbidden error
if request file did not exist (stat() failed) (This behavior was
unfriendly to other handlers)
- mod_compress compress.cache-dir layout differs from deflate.cache-dir
layout; file cache should be cleared (or renamed) when migrating from
mod_compress to mod_deflate
- mod_deflate does not issue Vary: Accept-Encoding if request does not
contain Accept-Encoding. The identity response can be cache by
proxies and served to clients. Historically, some proxies disabled
caching if any Vary: response was seen. If the Vary header is
desirable, mod_deflate code which checks for Accept-Encoding and
compression type can be moved down a few lines to be below the
setting of the Vary response header.
NB: r->tmp_buf == srv->tmp_buf (pointer is copied for quicker access)
NB: request read and write chunkqueues currently point to connection
chunkqueues; per-request and per-connection chunkqueues are
not distinct from one another
con->read_queue == r->read_queue
con->write_queue == r->write_queue
NB: in the future, a separate connection config may be needed for
connection-level module hooks. Similarly, might need to have
per-request chunkqueues separate from per-connection chunkqueues.
Should probably also have a request_reset() which is distinct from
connection_reset().
use global rather than passing around (server *) just for that
li_itostrn() and li_utostrn() return string length
(rather than requiring subsequent strlen() to find length)
convert all log_error_write() to log_error() and pass (log_error_st *)
use con->errh in preference to srv->errh (even though currently same)
avoid passing (server *) when previously used only for logging (errh)
quickly clear buffer instead of buffer_string_set_length(b, 0) or
buffer_reset(b). Avoids free() of large buffers about to be reused,
or buffers that are module-scoped, persistent, and reused.
(buffer_reset() should still be used with buffers in connection *con
when the data in the buffers is supplied by external, untrusted source)
Glenn Strauss
Mohammed Sadiq