ngx_http_upstream.c

Nginx是一个高性能的HTTP和反向代理服务器

        ngx_http_upstream_finalize_request(r, u,
                                           NGX_HTTP_INTERNAL_SERVER_ERROR);
        return;
    }

    if (u->buffer.last - u->buffer.pos >= (ssize_t) u->length) {
        if (u->input_filter(u->input_filter_ctx, 0) == NGX_ERROR) {
            ngx_http_upstream_finalize_request(r, u, NGX_ERROR);
            return;
        }

        ngx_http_upstream_finalize_request(r, u, 0);
        return;
    }

    rev->handler = ngx_http_upstream_process_body_in_memory;

    ngx_http_upstream_process_body_in_memory(rev);
}


static ngx_int_t
ngx_http_upstream_test_connect(ngx_connection_t *c)
{
    int        err;
    socklen_t  len;

#if (NGX_HAVE_KQUEUE)

    if (ngx_event_flags & NGX_USE_KQUEUE_EVENT)  {
        if (c->write->pending_eof) {
            c->log->action = "connecting to upstream";
            (void) ngx_connection_error(c, c->write->kq_errno,
                                    "kevent() reported that connect() failed");
            return NGX_ERROR;
        }

    } else
#endif
    {
        err = 0;
        len = sizeof(int);

        /*
         * BSDs and Linux return 0 and set a pending error in err
         * Solaris returns -1 and sets errno
         */

        if (getsockopt(c->fd, SOL_SOCKET, SO_ERROR, (void *) &err, &len)
            == -1)
        {
            err = ngx_errno;
        }

        if (err) {
            c->log->action = "connecting to upstream";
            (void) ngx_connection_error(c, err, "connect() failed");
            return NGX_ERROR;
        }
    }

    return NGX_OK;
}


static void
ngx_http_upstream_process_body_in_memory(ngx_event_t *rev)
{
    size_t                size;
    ssize_t               n;
    ngx_buf_t            *b;
    ngx_connection_t     *c;
    ngx_http_request_t   *r;
    ngx_http_upstream_t  *u;

    c = rev->data;
    r = c->data;
    u = r->upstream;

    ngx_log_debug0(NGX_LOG_DEBUG_HTTP, c->log, 0,
                   "http upstream process body on memory");

    if (rev->timedout) {
        ngx_connection_error(c, NGX_ETIMEDOUT, "upstream timed out");
        ngx_http_upstream_finalize_request(r, u, NGX_ETIMEDOUT);
        return;
    }

    b = &u->buffer;

    for ( ;; ) {

        size = b->end - b->last;

        if (size == 0) {
            ngx_log_error(NGX_LOG_ALERT, c->log, 0,
                          "upstream buffer is too small to read repsonse");
            ngx_http_upstream_finalize_request(r, u, NGX_ERROR);
            return;
        }

        n = c->recv(c, b->last, size);

        if (n == NGX_AGAIN) {
            break;
        }

        if (n == 0 || n == NGX_ERROR) {
            ngx_http_upstream_finalize_request(r, u, n);
            return;
        }

        if (u->input_filter(u->input_filter_ctx, n) == NGX_ERROR) {
            ngx_http_upstream_finalize_request(r, u, NGX_ERROR);
            return;
        }

        if (!rev->ready) {
            break;
        }
    }

    if (ngx_handle_read_event(rev, 0) == NGX_ERROR) {
        ngx_http_upstream_finalize_request(r, u, NGX_ERROR);
        return;
    }

    if (rev->active) {
        ngx_add_timer(rev, u->conf->read_timeout);

    } else if (rev->timer_set) {
        ngx_del_timer(rev);
    }
}


static void
ngx_http_upstream_send_response(ngx_http_request_t *r, ngx_http_upstream_t *u)
{
    int                        tcp_nodelay;
    ssize_t                    size;
    ngx_int_t                  rc;
    ngx_event_pipe_t          *p;
    ngx_connection_t          *c;
    ngx_pool_cleanup_t        *cl;
    ngx_pool_cleanup_file_t   *clf;
    ngx_http_core_loc_conf_t  *clcf;

    rc = ngx_http_send_header(r);

    if (rc == NGX_ERROR || rc > NGX_OK || r->post_action || r->header_only) {
        ngx_http_upstream_finalize_request(r, u, rc);
        return;
    }

    u->header_sent = 1;

    if (r->request_body && r->request_body->temp_file) {
        for (cl = r->pool->cleanup; cl; cl = cl->next) {
            if (cl->handler == ngx_pool_cleanup_file) {
                clf = cl->data;

                if (clf->fd == r->request_body->temp_file->file.fd) {
                    cl->handler(clf);
                    cl->handler = NULL;
                    r->request_body->temp_file->file.fd = NGX_INVALID_FILE;
                    break;
                }
            }
        }
    }

    c = r->connection;

    clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);

    if (!u->buffering) {

        if (u->input_filter == NULL) {
            u->input_filter_init = ngx_http_upstream_non_buffered_filter_init;
            u->input_filter = ngx_http_upstream_non_buffered_filter;
            u->input_filter_ctx = r;
        }

        u->peer.connection->read->handler =
                                   ngx_http_upstream_process_non_buffered_body;
        r->write_event_handler =
                             ngx_http_upstream_process_non_buffered_downstream;

        r->limit_rate = 0;

        if (u->input_filter_init(u->input_filter_ctx) == NGX_ERROR) {
            ngx_http_upstream_finalize_request(r, u, 0);
            return;
        }

        if (clcf->tcp_nodelay && c->tcp_nodelay == NGX_TCP_NODELAY_UNSET) {
            ngx_log_debug0(NGX_LOG_DEBUG_HTTP, c->log, 0, "tcp_nodelay");

            tcp_nodelay = 1;

            if (setsockopt(c->fd, IPPROTO_TCP, TCP_NODELAY,
                               (const void *) &tcp_nodelay, sizeof(int)) == -1)
            {
                ngx_connection_error(c, ngx_socket_errno,
                                     "setsockopt(TCP_NODELAY) failed");
                ngx_http_upstream_finalize_request(r, u, 0);
                return;
            }

            c->tcp_nodelay = NGX_TCP_NODELAY_SET;
        }

        size = u->buffer.last - u->buffer.pos;

        if (size) {
            u->buffer.last = u->buffer.pos;

            if (u->input_filter(u->input_filter_ctx, size) == NGX_ERROR) {
                ngx_http_upstream_finalize_request(r, u, 0);
                return;
            }

            ngx_http_upstream_process_non_buffered_body(c->write);

        } else {
            u->buffer.pos = u->buffer.start;
            u->buffer.last = u->buffer.start;

            if (ngx_http_send_special(r, NGX_HTTP_FLUSH) == NGX_ERROR) {
                ngx_http_upstream_finalize_request(r, u, 0);
                return;
            }

            if (u->peer.connection->read->ready) {
                ngx_http_upstream_process_non_buffered_body(
                                                     u->peer.connection->read);
            }
        }

        return;
    }

    /* TODO: preallocate event_pipe bufs, look "Content-Length" */

#if 0

    if (u->cache && u->cache->ctx.file.fd != NGX_INVALID_FILE) {
        if (ngx_close_file(u->cache->ctx.file.fd) == NGX_FILE_ERROR) {
            ngx_log_error(NGX_LOG_ALERT, c->log, ngx_errno,
                          ngx_close_file_n " \"%s\" failed",
                          u->cache->ctx.file.name.data);
        }
    }

    if (u->cacheable) {
        header = (ngx_http_cache_header_t *) u->buffer->start;

        header->expires = u->cache->ctx.expires;
        header->last_modified = u->cache->ctx.last_modified;
        header->date = u->cache->ctx.date;
        header->length = r->headers_out.content_length_n;
        u->cache->ctx.length = r->headers_out.content_length_n;

        header->key_len = u->cache->ctx.key0.len;
        ngx_memcpy(&header->key, u->cache->ctx.key0.data, header->key_len);
        header->key[header->key_len] = LF;
    }

#endif

    p = u->pipe;

    p->output_filter = (ngx_event_pipe_output_filter_pt) ngx_http_output_filter;
    p->output_ctx = r;
    p->tag = u->output.tag;
    p->bufs = u->conf->bufs;
    p->busy_size = u->conf->busy_buffers_size;
    p->upstream = u->peer.connection;
    p->downstream = c;
    p->pool = r->pool;
    p->log = c->log;

    p->cacheable = u->cacheable || u->store;

    p->temp_file = ngx_pcalloc(r->pool, sizeof(ngx_temp_file_t));
    if (p->temp_file == NULL) {
        ngx_http_upstream_finalize_request(r, u, 0);
        return;
    }

    p->temp_file->file.fd = NGX_INVALID_FILE;
    p->temp_file->file.log = c->log;
    p->temp_file->path = u->conf->temp_path;
    p->temp_file->pool = r->pool;

    if (u->cacheable || u->store) {
        p->temp_file->persistent = 1;

    } else {
        p->temp_file->log_level = NGX_LOG_WARN;
        p->temp_file->warn = "an upstream response is buffered "
                             "to a temporary file";
    }

    p->max_temp_file_size = u->conf->max_temp_file_size;
    p->temp_file_write_size = u->conf->temp_file_write_size;

    p->preread_bufs = ngx_alloc_chain_link(r->pool);
    if (p->preread_bufs == NULL) {
        ngx_http_upstream_finalize_request(r, u, 0);
        return;
    }

    p->preread_bufs->buf = &u->buffer;
    p->preread_bufs->next = NULL;
    u->buffer.recycled = 1;

    p->preread_size = u->buffer.last - u->buffer.pos;

    if (u->cacheable) {

        p->buf_to_file = ngx_calloc_buf(r->pool);
        if (p->buf_to_file == NULL) {
            ngx_http_upstream_finalize_request(r, u, 0);
            return;
        }

        p->buf_to_file->pos = u->buffer.start;
        p->buf_to_file->last = u->buffer.pos;
        p->buf_to_file->temporary = 1;
    }

    if (ngx_event_flags & NGX_USE_AIO_EVENT) {
        /* the posted aio operation may currupt a shadow buffer */
        p->single_buf = 1;
    }

    /* TODO: p->free_bufs = 0 if use ngx_create_chain_of_bufs() */
    p->free_bufs = 1;

    /*
     * event_pipe would do u->buffer.last += p->preread_size
     * as though these bytes were read
     */
    u->buffer.last = u->buffer.pos;

    if (u->conf->cyclic_temp_file) {

        /*
         * we need to disable the use of sendfile() if we use cyclic temp file
         * because the writing a new data may interfere with sendfile()
         * that uses the same kernel file pages (at least on FreeBSD)
         */

        p->cyclic_temp_file = 1;
        c->sendfile = 0;

    } else {
        p->cyclic_temp_file = 0;
    }

    p->read_timeout = u->conf->read_timeout;
    p->send_timeout = clcf->send_timeout;
    p->send_lowat = clcf->send_lowat;

    u->peer.connection->read->handler = ngx_http_upstream_process_body;
    r->write_event_handler = ngx_http_upstream_process_downstream;

    ngx_http_upstream_process_body(u->peer.connection->read);
}


static void
ngx_http_upstream_process_non_buffered_downstream(ngx_http_request_t *r)
{
    ngx_http_upstream_process_non_buffered_body(r->connection->write);
}


static void
ngx_http_upstream_process_non_buffered_body(ngx_event_t *ev)
{
    size_t                     size;
    ssize_t                    n;
    ngx_buf_t                 *b;
    ngx_int_t                  rc;
    ngx_uint_t                 do_write;
    ngx_connection_t          *c, *downstream, *upstream;
    ngx_http_request_t        *r;
    ngx_http_upstream_t       *u;
    ngx_http_core_loc_conf_t  *clcf;

    c = ev->data;
    r = c->data;
    u = r->upstream;

    if (ev->write) {
        ngx_log_debug0(NGX_LOG_DEBUG_HTTP, c->log, 0,
                       "http upstream process non buffered downstream");
        c->log->action = "sending to client";

    } else {
        ngx_log_debug0(NGX_LOG_DEBUG_HTTP, c->log, 0,
                       "http upstream process non buffered upstream");
        c->log->action = "reading upstream";
    }

    if (ev->timedout) {
        if (ev->write) {
            c->timedout = 1;
            ngx_connection_error(c, NGX_ETIMEDOUT, "client timed out");

        } else {
            ngx_connection_error(c, NGX_ETIMEDOUT, "upstream timed out");
        }

        ngx_http_upstream_finalize_request(r, u, 0);
        return;
    }

    downstream = r->connection;
    upstream = u->peer.connection;

    b = &u->buffer;

    clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);

    do_write = ev->write || u->length == 0;

    for ( ;; ) {

        if (do_write) {

            if (u->out_bufs || u->busy_bufs) {
                rc = ngx_http_output_filter(r, u->out_bufs);

                if (downstream->destroyed) {
                    return;
                }

                if (rc == NGX_ERROR) {
                    ngx_http_upstream_finalize_request(r, u, 0);
                    return;
                }

                ngx_chain_update_chains(&u->free_bufs, &u->busy_bufs,
                                        &u->out_bufs, u->output.tag);
            }

            if (u->busy_bufs == NULL) {

                if (u->length == 0
                    || upstream->read->eof
                    || upstream->read->error)
                {
                    ngx_http_upstream_finalize_request(r, u, 0);
                    return;
                }