ngx_http_proxy_module.c

Nginx ("engine x") 是一个高性能的 HTTP 和 反向代理 服务器

    plcf = ngx_http_get_module_loc_conf(r, ngx_http_proxy_module);

    u = ngx_pcalloc(r->pool, sizeof(ngx_http_upstream_t));
    if (u == NULL) {
        return NGX_HTTP_INTERNAL_SERVER_ERROR;
    }

    u->peer.log = r->connection->log;
    u->peer.log_error = NGX_ERROR_ERR;
#if (NGX_THREADS)
    u->peer.lock = &r->connection->lock;
#endif

    u->output.tag = (ngx_buf_tag_t) &ngx_http_proxy_module;

    u->conf = &plcf->upstream;

    u->create_request = ngx_http_proxy_create_request;
    u->reinit_request = ngx_http_proxy_reinit_request;
    u->process_header = ngx_http_proxy_process_status_line;
    u->abort_request = ngx_http_proxy_abort_request;
    u->finalize_request = ngx_http_proxy_finalize_request;

    if (plcf->redirects) {
        u->rewrite_redirect = ngx_http_proxy_rewrite_redirect;
    }

    u->buffering = plcf->upstream.buffering;

    u->pipe = ngx_pcalloc(r->pool, sizeof(ngx_event_pipe_t));
    if (u->pipe == NULL) {
        return NGX_HTTP_INTERNAL_SERVER_ERROR;
    }

    u->pipe->input_filter = ngx_event_pipe_copy_input_filter;

    u->accel = 1;

    r->upstream = u;

    rc = ngx_http_read_client_request_body(r, ngx_http_upstream_init);

    if (rc >= NGX_HTTP_SPECIAL_RESPONSE) {
        return rc;
    }

    return NGX_DONE;
}


static ngx_int_t
ngx_http_proxy_create_request(ngx_http_request_t *r)
{
    size_t                        len, loc_len, body_len;
    uintptr_t                     escape;
    ngx_buf_t                    *b;
    ngx_str_t                     method;
    ngx_uint_t                    i, unparsed_uri;
    ngx_chain_t                  *cl, *body;
    ngx_list_part_t              *part;
    ngx_table_elt_t              *header;
    ngx_http_upstream_t          *u;
    ngx_http_proxy_ctx_t         *p;
    ngx_http_script_code_pt       code;
    ngx_http_script_engine_t      e, le;
    ngx_http_proxy_loc_conf_t    *plcf;
    ngx_http_script_len_code_pt   lcode;

    u = r->upstream;

    plcf = ngx_http_get_module_loc_conf(r, ngx_http_proxy_module);

    p = ngx_pcalloc(r->pool, sizeof(ngx_http_proxy_ctx_t));
    if (p == NULL) {
        return NGX_HTTP_INTERNAL_SERVER_ERROR;
    }

    ngx_http_set_ctx(r, p, ngx_http_proxy_module);

    len = sizeof(ngx_http_proxy_version) - 1 + sizeof(CRLF) - 1;

    if (u->method.len) {
        /* HEAD was changed to GET to cache response */
        method = u->method;
        method.len++;

    } else if (plcf->method.len) {
        method = plcf->method;

    } else {
        method = r->method_name;
        method.len++;
    }

    len += method.len + u->conf->uri.len;

    escape = 0;

    loc_len = (r->valid_location && u->conf->uri.len) ? u->conf->location.len:
                                                        0;

    if (u->conf->uri.len == 0 && r->valid_unparsed_uri && r == r->main) {
        unparsed_uri = 1;
        len += r->unparsed_uri.len;

    } else {
        unparsed_uri = 0;
        if (r->quoted_uri || r->internal) {
            escape = 2 * ngx_escape_uri(NULL, r->uri.data + loc_len,
                                        r->uri.len - loc_len, NGX_ESCAPE_URI);
        }

        len += r->uri.len - loc_len + escape + sizeof("?") - 1 + r->args.len;
    }

    ngx_http_script_flush_no_cacheable_variables(r, plcf->flushes);

    if (plcf->body_set_len) {
        le.ip = plcf->body_set_len->elts;
        le.request = r;
        le.flushed = 1;
        body_len = 0;

        while (*(uintptr_t *) le.ip) {
            lcode = *(ngx_http_script_len_code_pt *) le.ip;
            body_len += lcode(&le);
        }

        p->internal_body_length = body_len;
        len += body_len;
    }

    le.ip = plcf->headers_set_len->elts;
    le.request = r;
    le.flushed = 1;

    while (*(uintptr_t *) le.ip) {
        while (*(uintptr_t *) le.ip) {
            lcode = *(ngx_http_script_len_code_pt *) le.ip;
            len += lcode(&le);
        }
        le.ip += sizeof(uintptr_t);
    }


    if (plcf->upstream.pass_request_headers) {
        part = &r->headers_in.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 (ngx_hash_find(&plcf->headers_set_hash, header[i].hash,
                              header[i].lowcase_key, header[i].key.len))
            {
                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;
    }

    cl = ngx_alloc_chain_link(r->pool);
    if (cl == NULL) {
        return NGX_ERROR;
    }

    cl->buf = b;


    /* the request line */

    b->last = ngx_copy(b->last, method.data, method.len);

    u->uri.data = b->last;

    if (unparsed_uri) {
        b->last = ngx_copy(b->last, r->unparsed_uri.data, r->unparsed_uri.len);

    } else {
        if (r->valid_location) {
            b->last = ngx_copy(b->last, u->conf->uri.data, u->conf->uri.len);
        }

        if (escape) {
            ngx_escape_uri(b->last, r->uri.data + loc_len,
                           r->uri.len - loc_len, NGX_ESCAPE_URI);
            b->last += r->uri.len - loc_len + escape;

        } else {
            b->last = ngx_copy(b->last, r->uri.data + loc_len,
                               r->uri.len - loc_len);
        }

        if (r->args.len > 0) {
            *b->last++ = '?';
            b->last = ngx_copy(b->last, r->args.data, r->args.len);
        }
    }

    u->uri.len = b->last - u->uri.data;

    b->last = ngx_cpymem(b->last, ngx_http_proxy_version,
                         sizeof(ngx_http_proxy_version) - 1);

    ngx_memzero(&e, sizeof(ngx_http_script_engine_t));

    e.ip = plcf->headers_set->elts;
    e.pos = b->last;
    e.request = r;
    e.flushed = 1;

    le.ip = plcf->headers_set_len->elts;

    while (*(uintptr_t *) le.ip) {
        lcode = *(ngx_http_script_len_code_pt *) le.ip;

        /* skip the header line name length */
        (void) lcode(&le);

        if (*(ngx_http_script_len_code_pt *) le.ip) {

            for (len = 0; *(uintptr_t *) le.ip; len += lcode(&le)) {
                lcode = *(ngx_http_script_len_code_pt *) le.ip;
            }

            e.skip = (len == sizeof(CRLF) - 1) ? 1 : 0;

        } else {
            e.skip = 0;
        }

        le.ip += sizeof(uintptr_t);

        while (*(uintptr_t *) e.ip) {
            code = *(ngx_http_script_code_pt *) e.ip;
            code((ngx_http_script_engine_t *) &e);
        }
        e.ip += sizeof(uintptr_t);
    }

    b->last = e.pos;


    if (plcf->upstream.pass_request_headers) {
        part = &r->headers_in.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 (ngx_hash_find(&plcf->headers_set_hash, header[i].hash,
                              header[i].lowcase_key, header[i].key.len))
            {
                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,
                           "http proxy header: \"%V: %V\"",
                           &header[i].key, &header[i].value);
        }
    }


    /* add "\r\n" at the header end */
    *b->last++ = CR; *b->last++ = LF;

    if (plcf->body_set) {
        e.ip = plcf->body_set->elts;
        e.pos = b->last;

        while (*(uintptr_t *) e.ip) {
            code = *(ngx_http_script_code_pt *) e.ip;
            code((ngx_http_script_engine_t *) &e);
        }

        b->last = e.pos;
    }

#if (NGX_DEBUG)
    {
    ngx_str_t  s;

    s.len = b->last - b->pos;
    s.data = b->pos;
    ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                   "http proxy header:\n\"%V\"", &s);
    }
#endif

    if (plcf->body_set == NULL && plcf->upstream.pass_request_body) {

        body = u->request_bufs;
        u->request_bufs = cl;

        while (body) {
            b = ngx_alloc_buf(r->pool);
            if (b == NULL) {
                return NGX_ERROR;
            }

            ngx_memcpy(b, body->buf, sizeof(ngx_buf_t));

            cl->next = ngx_alloc_chain_link(r->pool);
            if (cl->next == NULL) {
                return NGX_ERROR;
            }

            cl = cl->next;
            cl->buf = b;

            body = body->next;
        }

        b->flush = 1;

    } else {
        u->request_bufs = cl;
    }

    cl->next = NULL;

    return NGX_OK;
}


static ngx_int_t
ngx_http_proxy_reinit_request(ngx_http_request_t *r)
{
    ngx_http_proxy_ctx_t  *p;

    p = ngx_http_get_module_ctx(r, ngx_http_proxy_module);

    if (p == NULL) {
        return NGX_OK;
    }

    p->status = 0;
    p->status_count = 0;
    p->status_start = NULL;
    p->status_end = NULL;

    r->upstream->process_header = ngx_http_proxy_process_status_line;

    return NGX_OK;
}


static ngx_int_t
ngx_http_proxy_process_status_line(ngx_http_request_t *r)
{
    ngx_int_t              rc;
    ngx_http_upstream_t   *u;
    ngx_http_proxy_ctx_t  *p;

    p = ngx_http_get_module_ctx(r, ngx_http_proxy_module);

    if (p == NULL) {
        return NGX_HTTP_INTERNAL_SERVER_ERROR;
    }

    rc = ngx_http_proxy_parse_status_line(r, p);

    if (rc == NGX_AGAIN) {
        return rc;
    }

    u = r->upstream;

    if (rc == NGX_HTTP_PROXY_PARSE_NO_HEADER) {
        ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
                      "upstream sent no valid HTTP/1.0 header");

#if 0
        if (u->accel) {
            return NGX_HTTP_UPSTREAM_INVALID_HEADER;
        }
#endif

        r->http_version = NGX_HTTP_VERSION_9;
        u->headers_in.status_n = NGX_HTTP_OK;
        u->state->status = NGX_HTTP_OK;

        return NGX_OK;
    }

    u->headers_in.status_n = p->status;
    u->state->status = p->status;

    u->headers_in.status_line.len = p->status_end - p->status_start;
    u->headers_in.status_line.data = ngx_palloc(r->pool,
                                                u->headers_in.status_line.len);
    if (u->headers_in.status_line.data == NULL) {
        return NGX_HTTP_INTERNAL_SERVER_ERROR;
    }

    ngx_memcpy(u->headers_in.status_line.data, p->status_start,
               u->headers_in.status_line.len);

    ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                   "http proxy status %ui \"%V\"",
                   u->headers_in.status_n, &u->headers_in.status_line);

    u->process_header = ngx_http_proxy_process_header;

    return ngx_http_proxy_process_header(r);
}


static ngx_int_t
ngx_http_proxy_parse_status_line(ngx_http_request_t *r, ngx_http_proxy_ctx_t *p)
{
    u_char                ch;
    u_char               *pos;