Commit b201cf70 authored by Nick Kew's avatar Nick Kew
Browse files

Backport R452330: header editing in mod_headers

+1 niq, chrisd, wrowe


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.2.x@483732 13f79535-47bb-0310-9956-ffa450edef68
parent 000b82eb
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+2 −0
Changes for CHANGES: 2 added lines, 0 removed lines.
Original line number Diff line number Diff line
                                                        -*- coding: utf-8 -*-
Changes with Apache 2.2.4
  *) mod_headers: support regexp-based editing of HTTP headers [Nick Kew]
   * mod_proxy: Add explicit flushing feature.
     When Servlet container sends AJP body message with size 0,
     this means that Servlet container has asked for an explicit flush.
+0 −6
Changes for STATUS: 0 added lines, 6 removed lines.
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@@ -255,12 +255,6 @@ PATCHES PROPOSED TO BACKPORT FROM TRUNK:
       Trunk version works
     +1: trawick, jim, wrowe

   * mod_headers: support regexp-based manipulation
     http://svn.apache.org/viewvc?view=rev&revision=452330
     +1: niq, chrisd, wrowe
     chrisd: Note that the docs need to be back-ported, and
             new_features_2_4.xml revised too.

   * mod_ldap: Better detection and clean up of ldap connection
     that have been terminated by the ldap server.
     http://svn.apache.org/viewvc?view=rev&revision=472633
+36 −6
Changes for docs/manual/mod/mod_headers.xml: 36 added lines, 6 removed lines.
Original line number Diff line number Diff line
@@ -144,20 +144,29 @@ is available only in Apache 2.0</compatibility>
         MyHeader: D=3775428 t=991424704447256 mytext
       </example>
      </li>
      <li>Enable DAV to work with Apache running HTTP through SSL hardware
      (<a href="http://svn.haxx.se/users/archive-2006-03/0549.shtml"
      >problem description</a>) by replacing <var>https:</var> with
      <var>http:</var> in the <var>Destination</var> header:
      <example>
        RequestHeader edit Destination ^https: http: early
      </example>
      </li>

    </ol>
</section>

<directivesynopsis>
<name>RequestHeader</name>
<description>Configure HTTP request headers</description>
<syntax>RequestHeader set|append|add|unset <var>header</var>
[<var>value</var>] [early|env=[!]<var>variable</var>]</syntax>
<syntax>RequestHeader set|append|add|unset|edit <var>header</var>
[<var>value</var>] [<var>replacement</var>] [early|env=[!]<var>variable</var>]</syntax>
<contextlist><context>server config</context><context>virtual host</context>
<context>directory</context><context>.htaccess</context></contextlist>
<override>FileInfo</override>

<usage>
    <p>This directive can replace, merge or remove HTTP request
    <p>This directive can replace, merge, change or remove HTTP request
    headers. The header is modified just before the content handler
    is run, allowing incoming headers to be modified. The action it
    performs is determined by the first argument. This can be one
@@ -186,18 +195,28 @@ is available only in Apache 2.0</compatibility>
    <dd>The request header of this name is removed, if it exists. If
    there are multiple headers of the same name, all will be removed.
    <var>value</var> must be omitted.</dd>

    <dt><code>edit</code></dt>
    <dd>If this request header exists, its value is transformed according
    to a <glossary ref="regex">regular expression</glossary>
    search-and-replace.  The <var>value</var> argument is a <glossary
    ref="regex">regular expression</glossary>, and the <var>replacement</var>
    is a replacement string, which may contain backreferences.</dd>
    </dl>

    <p>This argument is followed by a header name, which can
    include the final colon, but it is not required. Case is
    ignored. For <code>add</code>, <code>append</code> and
    <code>set</code> a <var>value</var> is given as the third argument. If
    <code>set</code> a <var>value</var> is given as the third argument. If a
    <var>value</var> contains spaces, it should be surrounded by double
    quotes. For unset, no <var>value</var> should be given.
    <var>value</var> may be a character string, a string containing format
    specifiers or a combination of both. The supported format specifiers
    are the same as for the <directive module="mod_headers">Header</directive>,
    please have a look there for details.</p>
    please have a look there for details.  For <code>edit</code> both
    a <var>value</var> and a <var>replacement</var> are required, and are
    a <glossary ref="regex">regular expression</glossary> and a
    replacement string respectively.</p>

    <p>The <directive>RequestHeader</directive> directive may be followed by
    an additional argument, which may be used to specify conditions under
@@ -221,7 +240,7 @@ is available only in Apache 2.0</compatibility>
<directivesynopsis>
<name>Header</name>
<description>Configure HTTP response headers</description>
<syntax>Header [<var>condition</var>] set|append|add|unset|echo
<syntax>Header [<var>condition</var>] set|append|add|unset|echo|edit
<var>header</var> [<var>value</var>] [early|env=[!]<var>variable</var>]</syntax>
<contextlist><context>server config</context><context>virtual host</context>
<context>directory</context><context>.htaccess</context></contextlist>
@@ -271,6 +290,13 @@ is available only in Apache 2.0</compatibility>
    response headers. <var>header</var> may be a 
    <glossary ref="regex">regular expression</glossary>.
    <var>value</var> must be omitted.</dd>

    <dt><code>edit</code></dt>
    <dd>If this request header exists, its value is transformed according
    to a <glossary ref="regex">regular expression</glossary>
    search-and-replace.  The <var>value</var> argument is a <glossary
    ref="regex">regular expression</glossary>, and the <var>replacement</var>
    is a replacement string, which may contain backreferences.</dd>
    </dl>

    <p>This argument is followed by a <var>header</var> name, which
@@ -322,6 +348,10 @@ is available only in Apache 2.0</compatibility>
      more efficient than <code>%s</code>.</p>
    </note> 

    <p>For <code>edit</code> there is both a <var>value</var> argument
    which is a <glossary ref="regex">regular expression</glossary>,
    and an additional <var>replacement</var> string.</p>

    <p>The <directive>Header</directive> directive may be followed by an
    an additional argument, which may be used to specify conditions under
    which the action will be taken, or may be the keyword <code>early</code>
+57 −6
Changes for modules/metadata/mod_headers.c: 57 added lines, 6 removed lines.
Original line number Diff line number Diff line
@@ -89,7 +89,8 @@ typedef enum {
    hdr_set = 's',              /* set (replace old value) */
    hdr_append = 'm',           /* append (merge into any old value) */
    hdr_unset = 'u',            /* unset header */
    hdr_echo = 'e'              /* echo headers from request to response */
    hdr_echo = 'e',             /* echo headers from request to response */
    hdr_edit = 'r'              /* change value by regexp */
} hdr_actions;

/*
@@ -119,6 +120,7 @@ typedef struct {
    apr_array_header_t *ta;   /* Array of format_tag structs */
    ap_regex_t *regex;
    const char *condition_var;
    const char *subs;
} header_entry;

/* echo_do is used for Header echo to iterate through the request headers*/
@@ -348,6 +350,7 @@ static char *parse_format_string(apr_pool_t *p, header_entry *hdr, const char *s

    /* No string to parse with unset and echo commands */
    if (hdr->action == hdr_unset ||
        hdr->action == hdr_edit ||
        hdr->action == hdr_echo) {
        return NULL;
    }
@@ -368,6 +371,7 @@ static APR_INLINE const char *header_inout_cmd(cmd_parms *cmd,
                                               const char *action,
                                               const char *hdr,
                                               const char *value,
                                               const char *subs,
                                               const char *envclause)
{
    headers_conf *dirconf = indirconf;
@@ -392,10 +396,29 @@ static APR_INLINE const char *header_inout_cmd(cmd_parms *cmd,
        new->action = hdr_unset;
    else if (!strcasecmp(action, "echo"))
        new->action = hdr_echo;
    else if (!strcasecmp(action, "edit"))
        new->action = hdr_edit;
    else
        return "first argument must be 'add', 'set', 'append', 'unset' or "
               "'echo'.";
        return "first argument must be 'add', 'set', 'append', 'unset', "
               "'echo' or 'edit'.";

    if (new->action == hdr_edit) {
        if (subs == NULL) {
            return "Header edit requires a match and a substitution";
        }
        new->regex = ap_pregcomp(cmd->pool, value, AP_REG_EXTENDED);
        if (new->regex == NULL) {
            return "Header edit regex could not be compiled";
        }
        new->subs = subs;
    }
    else {
        /* there's no subs, so envclause is really that argument */
        if (envclause != NULL) {
            return "Too many arguments to directive";
        }
        envclause = subs;
    }
    if (new->action == hdr_unset) {
        if (value) {
            if (envclause) {
@@ -465,6 +488,7 @@ static const char *header_cmd(cmd_parms *cmd, void *indirconf,
    const char *hdr;
    const char *val;
    const char *envclause;
    const char *subs;

    action = ap_getword_conf(cmd->pool, &args);
    if (cmd->info == &hdr_out) {
@@ -478,6 +502,7 @@ static const char *header_cmd(cmd_parms *cmd, void *indirconf,
    }
    hdr = ap_getword_conf(cmd->pool, &args);
    val = *args ? ap_getword_conf(cmd->pool, &args) : NULL;
    subs = *args ? ap_getword_conf(cmd->pool, &args) : NULL;
    envclause = *args ? ap_getword_conf(cmd->pool, &args) : NULL;

    if (*args) {
@@ -485,7 +510,7 @@ static const char *header_cmd(cmd_parms *cmd, void *indirconf,
                           " has too many arguments", NULL);
    }

    return header_inout_cmd(cmd, indirconf, action, hdr, val, envclause);
    return header_inout_cmd(cmd, indirconf, action, hdr, val, subs, envclause);
}

/*
@@ -512,6 +537,26 @@ static char* process_tags(header_entry *hdr, request_rec *r)
    }
    return str ? str : "";
}
static const char *process_regexp(header_entry *hdr, const char *value,
                                  apr_pool_t *pool)
{
    unsigned int nmatch = 10;
    ap_regmatch_t pmatch[10];
    const char *subs;
    char *ret;
    int diffsz;
    if (ap_regexec(hdr->regex, value, nmatch, pmatch, 0)) {
        /* no match, nothing to do */
        return value;
    }
    subs = ap_pregsub(pool, hdr->subs, value, nmatch, pmatch);
    diffsz = strlen(subs) - (pmatch[0].rm_eo - pmatch[0].rm_so);
    ret = apr_palloc(pool, strlen(value) + 1 + diffsz);
    memcpy(ret, value, pmatch[0].rm_so);
    strcpy(ret + pmatch[0].rm_so, subs);
    strcat(ret, value + pmatch[0].rm_eo);
    return ret;
}

static int echo_header(echo_do *v, const char *key, const char *val)
{
@@ -528,7 +573,9 @@ static int echo_header(echo_do *v, const char *key, const char *val)
static void do_headers_fixup(request_rec *r, apr_table_t *headers,
                             apr_array_header_t *fixup, int early)
{
    echo_do v;
    int i;
    const char *val;

    for (i = 0; i < fixup->nelts; ++i) {
        header_entry *hdr = &((header_entry *) (fixup->elts))[i];
@@ -568,14 +615,18 @@ static void do_headers_fixup(request_rec *r, apr_table_t *headers,
            apr_table_unset(headers, hdr->header);
            break;
        case hdr_echo:
        {
            echo_do v;
            v.r = r;
            v.hdr = hdr;
            apr_table_do((int (*) (void *, const char *, const char *))
                         echo_header, (void *) &v, r->headers_in, NULL);
            break;
        case hdr_edit:
            val = apr_table_get(headers, hdr->header);
            if (val != NULL) {
                apr_table_setn(headers, hdr->header,
                               process_regexp(hdr, val, r->pool));
            }
            break;
        }
    }
}