ngx_http_header_filter_module.c

Nginx是一个高性能的HTTP和反向代理服务器

            host = cscf->server_name;

        } else if (r->headers_in.host) {
            host.len = r->headers_in.host_name_len;
            host.data = r->headers_in.host->value.data;

        } else {
            host.data = addr;

            if (ngx_http_server_addr(r, &host) != NGX_OK) {
                return NGX_ERROR;
            }
        }

#if (NGX_HTTP_SSL)
        if (r->connection->ssl) {
            len += sizeof("Location: https://") - 1
                   + host.len
                   + r->headers_out.location->value.len + 2;

            if (clcf->port_in_redirect && r->port != 443) {
                len += r->port_text->len;
            }

        } else
#endif
        {
            len += sizeof("Location: http://") - 1
                   + host.len
                   + r->headers_out.location->value.len + 2;

            if (clcf->port_in_redirect && r->port != 80) {
                len += r->port_text->len;
            }
        }

    } else {
        host.len = 0;
        host.data = NULL;
    }

    if (r->chunked) {
        len += sizeof("Transfer-Encoding: chunked" CRLF) - 1;
    }

    if (r->keepalive) {
        len += sizeof("Connection: keep-alive" CRLF) - 1;

        /*
         * MSIE and Opera ignore the "Keep-Alive: timeout=<N>" header.
         * MSIE keeps the connection alive for about 60-65 seconds.
         * Opera keeps the connection alive very long.
         * Mozilla keeps the connection alive for N plus about 1-10 seconds.
         * Konqueror keeps the connection alive for about N seconds.
         */

        if (clcf->keepalive_header) {
            len += sizeof("Keep-Alive: timeout=") - 1 + NGX_TIME_T_LEN + 2;
        }

    } else {
        len += sizeof("Connection: closed" CRLF) - 1;
    }

    part = &r->headers_out.headers.part;
    header = part->elts;

    for (i = 0; /* void */; i++) {

        if (i >= part->nelts) {
            if (part->next == NULL) {
                break;
            }

            part = part->next;
            header = part->elts;
            i = 0;
        }

        if (header[i].hash == 0) {
            continue;
        }

        len += header[i].key.len + sizeof(": ") - 1 + header[i].value.len
               + sizeof(CRLF) - 1;
    }

    b = ngx_create_temp_buf(r->pool, len);
    if (b == NULL) {
        return NGX_ERROR;
    }

    /* "HTTP/1.x " */
    b->last = ngx_cpymem(b->last, "HTTP/1.1 ", sizeof("HTTP/1.x ") - 1);

    /* status line */
    if (r->headers_out.status_line.len) {
        b->last = ngx_copy(b->last, r->headers_out.status_line.data,
                           r->headers_out.status_line.len);

    } else {
        b->last = ngx_copy(b->last, ngx_http_status_lines[status].data,
                           ngx_http_status_lines[status].len);
    }
    *b->last++ = CR; *b->last++ = LF;

    if (r->headers_out.server == NULL) {
        if (clcf->server_tokens) {
            p = (u_char *) ngx_http_server_full_string;
            len = sizeof(ngx_http_server_full_string) - 1;

        } else {
            p = (u_char *) ngx_http_server_string;
            len = sizeof(ngx_http_server_string) - 1;
        }

        b->last = ngx_cpymem(b->last, p, len);
    }

    if (r->headers_out.date == NULL) {
        b->last = ngx_cpymem(b->last, "Date: ", sizeof("Date: ") - 1);
        b->last = ngx_cpymem(b->last, ngx_cached_http_time.data,
                             ngx_cached_http_time.len);

        *b->last++ = CR; *b->last++ = LF;
    }

    if (r->headers_out.content_type.len) {
        b->last = ngx_cpymem(b->last, "Content-Type: ",
                             sizeof("Content-Type: ") - 1);
        p = b->last;
        b->last = ngx_copy(b->last, r->headers_out.content_type.data,
                           r->headers_out.content_type.len);

        if (r->headers_out.content_type_len == r->headers_out.content_type.len
            && r->headers_out.charset.len)
        {
            b->last = ngx_cpymem(b->last, "; charset=",
                                 sizeof("; charset=") - 1);
            b->last = ngx_copy(b->last, r->headers_out.charset.data,
                               r->headers_out.charset.len);

            /* update r->headers_out.content_type for possible logging */

            r->headers_out.content_type.len = b->last - p;
            r->headers_out.content_type.data = p;
        }

        *b->last++ = CR; *b->last++ = LF;
    }

    if (r->headers_out.content_length == NULL
        && r->headers_out.content_length_n >= 0)
    {
        b->last = ngx_sprintf(b->last, "Content-Length: %O" CRLF,
                              r->headers_out.content_length_n);
    }

    if (r->headers_out.last_modified == NULL
        && r->headers_out.last_modified_time != -1)
    {
        b->last = ngx_cpymem(b->last, "Last-Modified: ",
                             sizeof("Last-Modified: ") - 1);
        b->last = ngx_http_time(b->last, r->headers_out.last_modified_time);

        *b->last++ = CR; *b->last++ = LF;
    }

    if (host.data) {

        p = b->last + sizeof("Location: ") - 1;

        b->last = ngx_cpymem(b->last, "Location: http",
                             sizeof("Location: http") - 1);

#if (NGX_HTTP_SSL)
        if (r->connection->ssl) {
            *b->last++ ='s';
        }
#endif

        *b->last++ = ':'; *b->last++ = '/'; *b->last++ = '/';
        b->last = ngx_copy(b->last, host.data, host.len);

        if (clcf->port_in_redirect) {
#if (NGX_HTTP_SSL)
            if (r->connection->ssl) {
                if (r->port != 443) {
                    b->last = ngx_copy(b->last, r->port_text->data,
                                       r->port_text->len);
                }
            } else
#endif
            {
                if (r->port != 80) {
                    b->last = ngx_copy(b->last, r->port_text->data,
                                       r->port_text->len);
                }
            }
        }

        b->last = ngx_copy(b->last, r->headers_out.location->value.data,
                           r->headers_out.location->value.len);

        /* update r->headers_out.location->value for possible logging */

        r->headers_out.location->value.len = b->last - p;
        r->headers_out.location->value.data = p;
        r->headers_out.location->key.len = sizeof("Location: ") - 1;
        r->headers_out.location->key.data = (u_char *) "Location: ";

        *b->last++ = CR; *b->last++ = LF;
    }

    if (r->chunked) {
        b->last = ngx_cpymem(b->last, "Transfer-Encoding: chunked" CRLF,
                             sizeof("Transfer-Encoding: chunked" CRLF) - 1);
    }

    if (r->keepalive) {
        b->last = ngx_cpymem(b->last, "Connection: keep-alive" CRLF,
                             sizeof("Connection: keep-alive" CRLF) - 1);

        if (clcf->keepalive_header) {
            b->last = ngx_sprintf(b->last, "Keep-Alive: timeout=%T" CRLF,
                                  clcf->keepalive_header);
        }

    } else {
        b->last = ngx_cpymem(b->last, "Connection: close" CRLF,
                             sizeof("Connection: close" CRLF) - 1);
    }

    part = &r->headers_out.headers.part;
    header = part->elts;

    for (i = 0; /* void */; i++) {

        if (i >= part->nelts) {
            if (part->next == NULL) {
                break;
            }

            part = part->next;
            header = part->elts;
            i = 0;
        }

        if (header[i].hash == 0) {
            continue;
        }

        b->last = ngx_copy(b->last, header[i].key.data, header[i].key.len);
        *b->last++ = ':' ; *b->last++ = ' ' ;

        b->last = ngx_copy(b->last, header[i].value.data, header[i].value.len);
        *b->last++ = CR; *b->last++ = LF;
    }

    ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                   "%*s\n", (size_t) (b->last - b->pos), b->pos);

    /* the end of HTTP header */
    *b->last++ = CR; *b->last++ = LF;

    r->header_size = b->last - b->pos;

    if (r->header_only) {
        b->last_buf = 1;
    }

    out.buf = b;
    out.next = NULL;

    return ngx_http_write_filter(r, &out);
}


static ngx_int_t
ngx_http_header_filter_init(ngx_conf_t *cf)
{
    ngx_http_top_header_filter = ngx_http_header_filter;

    return NGX_OK;
}