[mod_echo] test module to echo request as response

test/debugging module to echo request back to client as response

(not part of build Makefile)

src/mod_echo.c

@@ -0,0 +1,145 @@
+/*
+ * mod_echo - test/debugging module to echo request back to client as response
+ *
+ * Copyright(c) 2021 Glenn Strauss gstrauss()gluelogic.com  All rights reserved
+ * License: BSD 3-clause (same as lighttpd)
+ *
+ * Note: module is hard-coded to handle requests to the exact uri-path: "/echo"
+ *
+ * Note: testing GET requests with Content-Length requires lighttpd.conf:
+ *   server.http-parseopts += ("method-get-body" => "enable")
+ */
+#include "first.h"
+
+#include <stdlib.h>
+
+#include "base.h"
+#include "fdevent.h"
+#include "http_chunk.h"
+#include "plugin.h"
+#include "request.h"
+#include "response.h"
+
+typedef struct {
+    PLUGIN_DATA;
+} plugin_data;
+
+INIT_FUNC(mod_echo_init) {
+    return calloc(1, sizeof(plugin_data));
+}
+
+#if 1 /*(would be simpler if not supporting streaming w/ bufmin)*/
+
+static handler_t mod_echo_request_body(request_st * const r) {
+    chunkqueue * const cq = &r->reqbody_queue;
+    chunkqueue_remove_finished_chunks(cq); /* unnecessary? */
+    off_t cqlen = chunkqueue_length(cq);
+    if ((r->conf.stream_response_body & FDEVENT_STREAM_RESPONSE_BUFMIN)
+        && r->resp_body_started) {
+        if (chunkqueue_length(&r->write_queue) > 65536 - 4096) {
+            /* wait for more data to be sent to client */
+            return HANDLER_WAIT_FOR_EVENT;
+        }
+        else {
+            if (cqlen > 65536) {
+                cqlen = 65536;
+                joblist_append(r->con);
+            }
+        }
+    }
+
+    if (0 != http_chunk_transfer_cqlen(r, cq, (size_t)cqlen))
+        return HANDLER_ERROR;
+
+    if (cq->bytes_out == (off_t)r->reqbody_length) {
+        /* sent all request body input */
+        http_response_backend_done(r);
+        return HANDLER_FINISHED;
+    }
+
+    cqlen = chunkqueue_length(cq);
+    if (cq->bytes_in != (off_t)r->reqbody_length && cqlen < 65536 - 16384) {
+        /*(r->conf.stream_request_body & FDEVENT_STREAM_REQUEST)*/
+        if (!(r->conf.stream_request_body & FDEVENT_STREAM_REQUEST_POLLIN)) {
+            r->conf.stream_request_body |= FDEVENT_STREAM_REQUEST_POLLIN;
+            r->con->is_readable = 1; /* trigger optimistic read from client */
+        }
+    }
+    return HANDLER_WAIT_FOR_EVENT;
+}
+
+SUBREQUEST_FUNC(mod_echo_handle_subrequest) {
+    UNUSED(p_d);
+
+    handler_t rc = mod_echo_request_body(r);
+    if (rc != HANDLER_WAIT_FOR_EVENT) return rc;
+
+    chunkqueue * const cq = &r->reqbody_queue;
+    if (cq->bytes_in != (off_t)r->reqbody_length) {
+        /*(64k - 4k to attempt to avoid temporary files
+         * in conjunction with FDEVENT_STREAM_REQUEST_BUFMIN)*/
+        if (chunkqueue_length(cq) > 65536 - 4096
+            && (r->conf.stream_request_body & FDEVENT_STREAM_REQUEST_BUFMIN)) {
+            r->conf.stream_request_body &= ~FDEVENT_STREAM_REQUEST_POLLIN;
+            return HANDLER_WAIT_FOR_EVENT;
+        }
+        else {
+            rc = r->con->reqbody_read(r);
+            if (rc != HANDLER_GO_ON) return rc;
+
+            if (-1 == r->reqbody_length
+                && !(r->conf.stream_request_body & FDEVENT_STREAM_REQUEST))
+                return HANDLER_WAIT_FOR_EVENT;
+        }
+    }
+
+    return mod_echo_request_body(r);
+}
+
+#else /*(would be simpler if not supporting streaming w/ bufmin (above))*/
+
+SUBREQUEST_FUNC(mod_echo_handle_subrequest) {
+    UNUSED(p_d);
+
+    handler_t rc = r->con->reqbody_read(r);
+    if (rc != HANDLER_GO_ON) return rc;
+
+    chunkqueue * const cq = &r->reqbody_queue;
+    if (0 != http_chunk_transfer_cqlen(r, cq, chunkqueue_length(cq)))
+        return HANDLER_ERROR;
+
+    if (cq->bytes_out == (off_t)r->reqbody_length) {
+        http_response_backend_done(r);
+        return HANDLER_FINISHED;
+    }
+    return HANDLER_WAIT_FOR_EVENT;
+}
+
+#endif
+
+URIHANDLER_FUNC(mod_echo_handle_uri_clean) {
+    plugin_data *p = p_d;
+    if (NULL == r->handler_module
+        && buffer_eq_slen(&r->uri.path, CONST_STR_LEN("/echo"))) {
+        r->handler_module = p->self;
+        r->resp_body_started = 1;
+        /* XXX: future: might echo request headers here */
+        if (0 == r->reqbody_length) {
+            r->resp_body_finished = 1;
+            return HANDLER_FINISHED;
+        }
+    }
+    return HANDLER_GO_ON;
+}
+
+int mod_echo_plugin_init(plugin *p);
+int mod_echo_plugin_init(plugin *p) {
+    p->version                 = LIGHTTPD_VERSION_ID;
+    p->name                    = "echo";
+
+    p->handle_uri_clean        = mod_echo_handle_uri_clean;
+    p->handle_subrequest       = mod_echo_handle_subrequest;
+    p->init                    = mod_echo_init;
+
+    return 0;
+}