http_accept
| Rivet Tcl Commands and Variables |

## Name

http_accept — Parse HTTP Accept header lines

## Synopsis

::rivet::http_accept ?`-zeroweight`? ?`-default`? ?`-list`? http_accept_line

## Description

Command for parsing HTTP Accept header lines that tell the server about preferences and/or capabilities of the browser (e.g. content language,media type, etc.). The following script

::rivet::http_accept returns a dictionary value in which every content preference is matched to its precedence value

    load_headers
    set language_precedence [::rivet::http_accept $headers(Accept-Language)]
    foreach lan [dict keys $language_precedence] {
                    puts "$lan -> [dict get $language_precedence $lan]"
    }

when run from a browser where 5 languages were chosen would output

    en-us -> 1
    en -> 0.8
    it -> 0.6
    de-de -> 0.4
    fr-fr -> 0.2

The `-list` switch would suppress the precedence values and the accepted fields are returned listed with decreasing precedence order.

     puts [::rivet::http_accept -list $headers(Accept-Language)]
    text/html application/xhtml+xml application/xml */*

html |  | import_keyvalue_pairs