vmod_bodyaccess - Man Page

Varnish Module for request body access

Synopsis

import bodyaccess [as name] [from "path"]

INT rematch_req_body(STRING re)

VOID hash_req_body()

INT len_req_body()

VOID log_req_body(STRING prefix, INT length)

Description

Varnish module that lets you access the request body.

VCL example:

vcl 4.0;
import std;
import bodyaccess;

backend default { .host = "192.0.2.11"; .port = "8080"; }

sub vcl_recv {
        if (req.method == "POST") {
                set req.http.x-method = req.method;
                if (std.cache_req_body(110KB)) {
                        set req.http.x-len = bodyaccess.len_req_body();
                        set req.http.x-re = bodyaccess.rematch_req_body("Regex");
                        bodyaccess.log_req_body("PREFIX:", 3);
                }
        }
return(hash);
}

sub vcl_hash {
        bodyaccess.hash_req_body();
        return (lookup);
}

sub vcl_backend_fetch {
        set bereq.method = bereq.http.x-method;
}

sub vcl_deliver {
        set resp.http.x-len = req.http.x-len;
        set resp.http.x-re = req.http.x-re;
}

N.B. The request body must be retrieved before doing any operations on it. It can be buffered using the cache_req_body() function from libvmod_std.

These functions applies only to standard REST methods. Caching is not allowed on PUT requests.

INT rematch_req_body(STRING re)

Description

Returns -1 if an error occurrs. Returns 0 if the request body doesn't contain the string re. Returns 1 if the request body contains the string re.

Note that the comparison is case sensitive and the request body must be buffered.

Example
| std.cache_req_body(1KB);
|
| if (bodyaccess.rematch_req_body("FOO") == 1) {
|    std.log("is true");
| }

VOID hash_req_body()

Description

Adds available request body bytes to the lookup hash key. Note that this function can only be used in vcl_hash and the request body must be buffered.

Example
| sub vcl_recv {
|     std.cache_req_body(1KB);
| }
|
| sub vcl_hash{
|     bodyaccess.hash_req_body();
| }

INT len_req_body()

Description

Returns the request body length or -1 if an error occurs.

Note that the request body must be buffered.

Example
| std.cache_req_body(1KB);
| set req.http.x-len = bodyaccess.len_req_body();

VOID log_req_body(STRING prefix=“”, INT length=200)

Description

Log the request body to the VSL, making it available for other components. When logging, it takes an optional prefix and a max line length, so the body could be split up across multiple lines as there is a limit to how large a single line can be.

Example
| std.cache_req_body(1KB);
| bodyaccess.log_req_body("PREFIX:", 3);