From: Graham Leggett Date: Mon, 1 Feb 2010 20:43:01 +0000 (+0000) Subject: Allow fine control over the removal of Last-Modified and ETag headers X-Git-Tag: 2.3.6~534 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=d9ea2d64c06df45e529bdc2aee10e448b354f20a;p=thirdparty%2Fapache%2Fhttpd.git Allow fine control over the removal of Last-Modified and ETag headers within the INCLUDES filter, making it possible to cache responses if desired. Fix the default value of the SSIAccessEnable directive. git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@905406 13f79535-47bb-0310-9956-ffa450edef68 --- diff --git a/CHANGES b/CHANGES index af191baea33..7c29c5e81f8 100644 --- a/CHANGES +++ b/CHANGES @@ -2,6 +2,11 @@ Changes with Apache 2.3.6 + *) Allow fine control over the removal of Last-Modified and ETag headers + within the INCLUDES filter, making it possible to cache responses if + desired. Fix the default value of the SSIAccessEnable directive. + [Graham Leggett] + *) Allow the Define directive to undefine a variable by prefixing the argument with a '!'. PR 35350. [Stefan Fritsch] diff --git a/docs/manual/mod/mod_include.xml b/docs/manual/mod/mod_include.xml index e08204ccd3c..e9b3a8c8cc4 100644 --- a/docs/manual/mod/mod_include.xml +++ b/docs/manual/mod/mod_include.xml @@ -809,6 +809,84 @@ displayed + +SSIETag +Controls whether ETags are generated by the server. +SSIETag on|off +SSIETag off +directory.htaccess + + +

Under normal circumstances, a file filtered by mod_include + may contain elements that are either dynamically generated, or that may + have changed independently of the original file. As a result, by default + the server is asked not to generate an ETag header for the + response by adding no-etag to the request notes.

+ +

The SSIETag directive suppresses this + behaviour, and allows the server to generate an ETag header. + This can be used to enable caching of the output. Note that a backend server + or dynamic content generator may generate an ETag of its own, ignoring + no-etag, and this ETag will be passed by + mod_include regardless of the value of this setting. + SSIETag can take on the following values:

+ +
+ +
off
+
no-etag will be added to the request notes, and the server + is asked not to generate an ETag. Where a server ignores the value of + no-etag and generates an ETag anyway, the ETag will be + respected.
+ +
on
+
Existing ETags will be respected, and ETags generated by the server will + be passed on in the response.
+ +
+ + + + + +SSILastModified +Controls whether Last-Modified headers are generated by the +server. +SSILastModified on|off +SSILastModified off +directory.htaccess + + +

Under normal circumstances, a file filtered by mod_include + may contain elements that are either dynamically generated, or that may + have changed independently of the original file. As a result, by default + the Last-Modified header is stripped from the response.

+ +

The SSILastModified directive overrides this + behaviour, and allows the Last-Modified header to be respected + if already present, or set if the header is not already present. This can + be used to enable caching of the output. SSILastModified + can take on the following values:

+ +
+ +
off
+
The Last-Modified header will be stripped from responses, + unless the XBitHack directive + is set to full as described below.
+ +
on
+
The Last-Modified header will be respected if already + present in a response, and added to the response if the response is a + file and the header is missing. The + SSILastModified directive + takes precedence over XBitHack.
+ +
+ + + + XBitHack Parse SSI directives in files with the execute bit @@ -846,7 +924,14 @@ set group-execute bit is unset for every SSI script which might #include a CGI or otherwise produces different output on each hit (or could potentially change on subsequent requests).

+ +

The SSILastModified + directive takes precedence over the + XBitHack directive when + SSILastModified is set to + on.

+ diff --git a/modules/filters/mod_include.c b/modules/filters/mod_include.c index 8c91d331433..e3234e3907d 100644 --- a/modules/filters/mod_include.c +++ b/modules/filters/mod_include.c @@ -77,7 +77,9 @@ typedef struct { const char *default_time_fmt; const char *undefined_echo; xbithack_t xbithack; - const int accessenable; + int accessenable; + int lastmodified; + int etag; } include_dir_config; typedef struct { @@ -417,6 +419,9 @@ static const char lazy_eval_sentinel; #define DEFAULT_ERROR_MSG "[an error occurred while processing this directive]" #define DEFAULT_TIME_FORMAT "%A, %d-%b-%Y %H:%M:%S %Z" #define DEFAULT_UNDEFINED_ECHO "(none)" +#define DEFAULT_ACCESSENABLE 0 +#define DEFAULT_LASTMODIFIED 0 +#define DEFAULT_ETAG 0 #ifdef XBITHACK #define DEFAULT_XBITHACK XBITHACK_FULL @@ -897,7 +902,7 @@ static int ssi_access(request_rec *r, ap_parse_node_t *current, } else { current->value = 0; - ap_log_rerror(APLOG_MARK, APLOG_DEBUG, rr->status, r, + ap_log_rerror(APLOG_MARK, APLOG_DEBUG, rr->status, r, "mod_include: The tested " "subrequest -A \"%s\" returned an error code.", current->right->token.value); @@ -2911,7 +2916,9 @@ static int includes_setup(ap_filter_t *f) * We don't know if we are going to be including a file or executing * a program - in either case a strong ETag header will likely be invalid. */ - apr_table_setn(f->r->notes, "no-etag", ""); + if (!conf->etag) { + apr_table_setn(f->r->notes, "no-etag", ""); + } return OK; } @@ -3014,13 +3021,32 @@ static apr_status_t includes_filter(ap_filter_t *f, apr_bucket_brigade *b) * a program which may change the Last-Modified header or make the * content completely dynamic. Therefore, we can't support these * headers. - * Exception: XBitHack full means we *should* set the Last-Modified field. + * + * Exception: XBitHack full means we *should* set the + * Last-Modified field. + * + * SSILastModified on means we *should* set the Last-Modified field + * if not present, or respect an existing value if present. */ + /* Must we respect the last modified header? By default, no */ + if (conf->lastmodified) { + + /* update the last modified if we have a valid time, and only if + * we don't already have a valid last modified. + */ + if (r->finfo.valid & APR_FINFO_MTIME + && !apr_table_get(f->r->headers_out, "Last-Modified")) { + ap_update_mtime(r, r->finfo.mtime); + ap_set_last_modified(r); + } + + } + /* Assure the platform supports Group protections */ - if ((conf->xbithack == XBITHACK_FULL) + else if (((conf->xbithack == XBITHACK_FULL) && (r->finfo.valid & APR_FINFO_GPROT) - && (r->finfo.protection & APR_GEXECUTE)) { + && (r->finfo.protection & APR_GEXECUTE))) { ap_update_mtime(r, r->finfo.mtime); ap_set_last_modified(r); } @@ -3100,6 +3126,9 @@ static void *create_includes_dir_config(apr_pool_t *p, char *dummy) result->default_time_fmt = DEFAULT_TIME_FORMAT; result->undefined_echo = DEFAULT_UNDEFINED_ECHO; result->xbithack = DEFAULT_XBITHACK; + result->accessenable = DEFAULT_ACCESSENABLE; + result->lastmodified = DEFAULT_LASTMODIFIED; + result->etag = DEFAULT_ETAG; return result; } @@ -3252,6 +3281,14 @@ static const command_rec includes_cmds[] = AP_INIT_FLAG("SSIAccessEnable", ap_set_flag_slot, (void *)APR_OFFSETOF(include_dir_config, accessenable), OR_LIMIT, "Whether testing access is enabled. Limited to 'on' or 'off'"), + AP_INIT_FLAG("SSILastModified", ap_set_flag_slot, + (void *)APR_OFFSETOF(include_dir_config, lastmodified), + OR_LIMIT, "Whether to set the last modified header or respect " + "an existing header. Limited to 'on' or 'off'"), + AP_INIT_FLAG("SSIEtag", ap_set_flag_slot, + (void *)APR_OFFSETOF(include_dir_config, etag), + OR_LIMIT, "Whether to allow the generation of ETags within the server. " + "Existing ETags will be preserved. Limited to 'on' or 'off'"), {NULL} };