in modules/filters/mod_brotli.c [330:569]
static apr_status_t compress_filter(ap_filter_t *f, apr_bucket_brigade *bb)
{
request_rec *r = f->r;
brotli_ctx_t *ctx = f->ctx;
apr_status_t rv;
brotli_server_config_t *conf;
if (APR_BRIGADE_EMPTY(bb)) {
return APR_SUCCESS;
}
conf = ap_get_module_config(r->server->module_config, &brotli_module);
if (!ctx) {
const char *encoding;
const char *token;
const char *accepts;
const char *q = NULL;
/* Only work on main request, not subrequests, that are not
* a 204 response with no content, and are not tagged with the
* no-brotli env variable, and are not a partial response to
* a Range request.
*
* Note that responding to 304 is handled separately to set
* the required headers (such as ETag) per RFC7232, 4.1.
*/
if (r->main || r->status == HTTP_NO_CONTENT
|| apr_table_get(r->subprocess_env, "no-brotli")
|| apr_table_get(r->headers_out, "Content-Range")) {
ap_remove_output_filter(f);
return ap_pass_brigade(f->next, bb);
}
/* Let's see what our current Content-Encoding is. */
encoding = get_content_encoding(r);
if (encoding) {
const char *tmp = encoding;
token = ap_get_token(r->pool, &tmp, 0);
while (token && *token) {
if (strcmp(token, "identity") != 0 &&
strcmp(token, "7bit") != 0 &&
strcmp(token, "8bit") != 0 &&
strcmp(token, "binary") != 0) {
/* The data is already encoded, do nothing. */
ap_remove_output_filter(f);
return ap_pass_brigade(f->next, bb);
}
if (*tmp) {
++tmp;
}
token = (*tmp) ? ap_get_token(r->pool, &tmp, 0) : NULL;
}
}
/* Even if we don't accept this request based on it not having
* the Accept-Encoding, we need to note that we were looking
* for this header and downstream proxies should be aware of
* that.
*/
apr_table_mergen(r->headers_out, "Vary", "Accept-Encoding");
accepts = apr_table_get(r->headers_in, "Accept-Encoding");
if (!accepts) {
ap_remove_output_filter(f);
return ap_pass_brigade(f->next, bb);
}
/* Do we have Accept-Encoding: br? */
token = ap_get_token(r->pool, &accepts, 0);
while (token && token[0] && ap_cstr_casecmp(token, "br") != 0) {
while (*accepts == ';') {
++accepts;
ap_get_token(r->pool, &accepts, 1);
}
if (*accepts == ',') {
++accepts;
}
token = (*accepts) ? ap_get_token(r->pool, &accepts, 0) : NULL;
}
/* Find the qvalue, if provided */
if (*accepts) {
while (*accepts == ';') {
++accepts;
}
q = ap_get_token(r->pool, &accepts, 1);
ap_log_rerror(APLOG_MARK, APLOG_TRACE1, 0, r,
"token: '%s' - q: '%s'", token ? token : "NULL", q);
}
/* No acceptable token found or q=0 */
if (!token || token[0] == '\0' ||
(q && strlen(q) >= 3 && strncmp("q=0.000", q, strlen(q)) == 0)) {
ap_remove_output_filter(f);
return ap_pass_brigade(f->next, bb);
}
/* If the entire Content-Encoding is "identity", we can replace it. */
if (!encoding || ap_cstr_casecmp(encoding, "identity") == 0) {
apr_table_setn(r->headers_out, "Content-Encoding", "br");
} else {
apr_table_mergen(r->headers_out, "Content-Encoding", "br");
}
if (r->content_encoding) {
r->content_encoding = apr_table_get(r->headers_out,
"Content-Encoding");
}
apr_table_unset(r->headers_out, "Content-Length");
apr_table_unset(r->headers_out, "Content-MD5");
/* https://bz.apache.org/bugzilla/show_bug.cgi?id=39727
* https://bz.apache.org/bugzilla/show_bug.cgi?id=45023
*
* ETag must be unique among the possible representations, so a
* change to content-encoding requires a corresponding change to the
* ETag. We make this behavior configurable, and mimic mod_deflate's
* DeflateAlterETag with BrotliAlterETag to keep the transition from
* mod_deflate seamless.
*/
if (conf->etag_mode == ETAG_MODE_REMOVE) {
apr_table_unset(r->headers_out, "ETag");
}
else if (conf->etag_mode == ETAG_MODE_ADDSUFFIX) {
const char *etag = apr_table_get(r->headers_out, "ETag");
if (etag) {
apr_size_t len = strlen(etag);
if (len > 2 && etag[len - 1] == '"') {
etag = apr_pstrmemdup(r->pool, etag, len - 1);
etag = apr_pstrcat(r->pool, etag, "-br\"", NULL);
apr_table_setn(r->headers_out, "ETag", etag);
}
}
}
/* For 304 responses, we only need to send out the headers. */
if (r->status == HTTP_NOT_MODIFIED) {
ap_remove_output_filter(f);
return ap_pass_brigade(f->next, bb);
}
ctx = create_ctx(conf->quality, conf->lgwin, conf->lgblock,
f->c->bucket_alloc, r->pool);
f->ctx = ctx;
}
while (!APR_BRIGADE_EMPTY(bb)) {
apr_bucket *e = APR_BRIGADE_FIRST(bb);
/* Optimization: If we are a HEAD request and bytes_sent is not zero
* it means that we have passed the content-length filter once and
* have more data to send. This means that the content-length filter
* could not determine our content-length for the response to the
* HEAD request anyway (the associated GET request would deliver the
* body in chunked encoding) and we can stop compressing.
*/
if (r->header_only && r->bytes_sent) {
ap_remove_output_filter(f);
return ap_pass_brigade(f->next, bb);
}
if (APR_BUCKET_IS_EOS(e)) {
rv = flush(ctx, BROTLI_OPERATION_FINISH, f);
if (rv != APR_SUCCESS) {
return rv;
}
/* Leave notes for logging. */
if (conf->note_input_name) {
apr_table_setn(r->notes, conf->note_input_name,
apr_off_t_toa(r->pool, ctx->total_in));
}
if (conf->note_output_name) {
apr_table_setn(r->notes, conf->note_output_name,
apr_off_t_toa(r->pool, ctx->total_out));
}
if (conf->note_ratio_name) {
if (ctx->total_in > 0) {
int ratio = (int) (ctx->total_out * 100 / ctx->total_in);
apr_table_setn(r->notes, conf->note_ratio_name,
apr_itoa(r->pool, ratio));
}
else {
apr_table_setn(r->notes, conf->note_ratio_name, "-");
}
}
APR_BUCKET_REMOVE(e);
APR_BRIGADE_INSERT_TAIL(ctx->bb, e);
rv = ap_pass_brigade(f->next, ctx->bb);
apr_brigade_cleanup(ctx->bb);
apr_pool_cleanup_run(r->pool, ctx, cleanup_ctx);
return rv;
}
else if (APR_BUCKET_IS_FLUSH(e)) {
rv = flush(ctx, BROTLI_OPERATION_FLUSH, f);
if (rv != APR_SUCCESS) {
return rv;
}
APR_BUCKET_REMOVE(e);
APR_BRIGADE_INSERT_TAIL(ctx->bb, e);
rv = ap_pass_brigade(f->next, ctx->bb);
apr_brigade_cleanup(ctx->bb);
if (rv != APR_SUCCESS) {
return rv;
}
}
else if (APR_BUCKET_IS_METADATA(e)) {
APR_BUCKET_REMOVE(e);
APR_BRIGADE_INSERT_TAIL(ctx->bb, e);
}
else {
const char *data;
apr_size_t len;
rv = apr_bucket_read(e, &data, &len, APR_BLOCK_READ);
if (rv != APR_SUCCESS) {
return rv;
}
rv = process_chunk(ctx, data, len, f);
if (rv != APR_SUCCESS) {
return rv;
}
apr_bucket_delete(e);
}
}
return APR_SUCCESS;
}