Refactored httpd server integration, split http support and server logic in two modules. Added functions to load component implementations packaged as dynamic libraries. Minor monad code cleanup, converted cast operators to separate functions.

git-svn-id: http://svn.us.apache.org/repos/asf/tuscany@883249 13f79535-47bb-0310-9956-ffa450edef68

1 files changed, 247 insertions, 0 deletions

diff --git a/sca-cpp/trunk/modules/server/mod-wiring.cpp b/sca-cpp/trunk/modules/server/mod-wiring.cpp
new file mode 100644
index 0000000000..2d3c8ce045
--- /dev/null
+++ b/sca-cpp/trunk/modules/server/mod-wiring.cpp
@@ -0,0 +1,247 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/* $Rev$ $Date$ */
+
+/**
+ * HTTPD module used to wire component references.
+ */
+
+#include <sys/stat.h>
+
+#include <string>
+#include <iostream>
+#include <sstream>
+#include <fstream>
+
+#include "list.hpp"
+#include "slist.hpp"
+#include "value.hpp"
+#include "monad.hpp"
+#include "cache.hpp"
+#include "../scdl/scdl.hpp"
+#include "../http/httpd.hpp"
+
+extern "C" {
+extern module AP_MODULE_DECLARE_DATA mod_tuscany_wiring;
+}
+
+namespace tuscany {
+namespace server {
+namespace modwiring {
+
+/**
+ * Server configuration.
+ */
+class ServerConf {
+public:
+    ServerConf(server_rec* s) : home("") {
+    }
+    server_rec* s;
+    std::string home;
+};
+
+/**
+ * Set to true to wire using mod_proxy, false to wire using HTTP client redirects.
+ */
+const bool useModProxy = true;
+
+/**
+ * Directory configuration.
+ */
+class DirConf {
+public:
+    DirConf(char* dirspec) : contributionPath(""), compositeName("") {
+    }
+    char* dirspec;
+    std::string contributionPath;
+    std::string compositeName;
+    cached<failable<list<value>, std::string> > components;
+};
+
+/**
+ * Read the SCDL configuration of the deployed components.
+ */
+const failable<list<value>, std::string> readComponents(const std::string& path) {
+    std::ifstream is(path);
+    if (is.fail() || is.bad())
+        return mkfailure<list<value>, std::string>("Could not read composite: " + path);
+    return scdl::components(readXML(streamList(is)));
+}
+
+const cached<failable<list<value>, std::string> > components(DirConf* conf) {
+    const std::string path(conf->contributionPath + conf->compositeName);
+    const lambda<failable<list<value>, std::string>(std::string)> rc(readComponents);
+    const lambda<unsigned long(std::string)> ft(latestFileTime);
+    return cached<failable<list<value>, std::string> >(curry(rc, path), curry(ft, path));
+}
+
+/**
+ * Returns true if a URI is absolute.
+ */
+const bool isAbsolute(const std::string& uri) {
+    return uri.find("://") != std::string::npos;
+}
+
+/**
+ * Translate an HTTP request URI. Wire a URI in the form /references/component-name/reference-name
+ * to the target of the reference.
+ */
+int translate(request_rec *r) {
+    if (strncmp(r->uri, "/references/", 12) != 0)
+        return DECLINED;
+    httpd::logRequest(r, "mod_tuscany_wiring::translate");
+
+    // Find the requested component, reference and its target configuration
+    DirConf& conf = httpd::dirConf<DirConf>(r, &mod_tuscany_wiring);
+    conf.components = latest(conf.components);
+    const failable<list<value>, std::string> comps(content(conf.components));
+    if (!hasContent(comps))
+        return HTTP_INTERNAL_SERVER_ERROR;
+    const list<value> rpath(httpd::path(r->uri));
+    const value comp(scdl::named(cadr(rpath), list<value>(content(comps))));
+    if (isNil(comp))
+        return HTTP_NOT_FOUND;
+    const value ref(scdl::named(caddr(rpath), scdl::references(comp)));
+    if (isNil(ref))
+        return HTTP_NOT_FOUND;
+    const std::string target(scdl::target(ref));
+
+    // Absolute target URI
+    if (isAbsolute(target)) {
+
+        // Wire using mod_proxy
+        if (useModProxy) {
+            r->filename = apr_pstrdup(r->pool, std::string("proxy:" + target).c_str());
+            r->proxyreq = PROXYREQ_REVERSE;
+            r->handler = "proxy-server";
+            return OK;
+        }
+
+        // Wire using an HTTP client redirect
+        r->status = HTTP_MOVED_TEMPORARILY;
+        apr_table_setn(r->headers_out, "Location", apr_pstrdup(r->pool, target.c_str()));
+        r->handler = "mod_tuscany_wiring";
+        return OK;
+
+    }
+
+    // Local internal redirect
+    r->filename = apr_pstrdup(r->pool, std::string("/redirect:/" + target).c_str());
+    r->handler = "mod_tuscany_wiring";
+    return OK;
+}
+
+/**
+ * Construct a redirect URI.
+ */
+const std::string redirect(const std::string& file, const std::string& pi) {
+    return file + pi;
+}
+
+const std::string redirect(const std::string& file, const std::string& pi, const std::string& args) {
+    return file + pi + "?" + args;
+}
+
+/**
+ * HTTP request internal redirect handler.
+ */
+int handler(request_rec *r) {
+    if(strcmp(r->handler, "mod_tuscany_wiring"))
+        return DECLINED;
+    httpd::logRequest(r, "mod_tuscany_wiring::handler");
+
+    // Do an internal redirect
+    if (r->filename == NULL || strncmp(r->filename, "/redirect:", 10) != 0)
+        return DECLINED;
+    if (r->args == NULL) {
+        ap_internal_redirect(apr_pstrdup(r->pool, redirect(r->filename + 10, r->path_info).c_str()), r);
+        return OK;
+    }
+    ap_internal_redirect(apr_pstrdup(r->pool, redirect(r->filename + 10, r->path_info, r->args).c_str()), r);
+    return OK;
+}
+
+/**
+ * Configuration commands.
+ */
+const char *confHome(cmd_parms *cmd, void *dummy, const char *arg) {
+    ServerConf *c = (ServerConf*)ap_get_module_config(cmd->server->module_config, &mod_tuscany_wiring);
+    c->home = arg;
+    return NULL;
+}
+const char *confContribution(cmd_parms *cmd, void *c, const char *arg) {
+    DirConf* conf = (DirConf*)c;
+    conf->contributionPath = arg;
+    conf->components = components(conf);
+    return NULL;
+}
+const char *confComposite(cmd_parms *cmd, void *c, const char *arg) {
+    DirConf* conf = (DirConf*)c;
+    conf->compositeName = arg;
+    conf->components = components(conf);
+    return NULL;
+}
+
+/**
+ * HTTP server module declaration.
+ */
+const command_rec commands[] = {
+    AP_INIT_TAKE1("TuscanyHome", (const char*(*)())confHome, NULL, RSRC_CONF, "Tuscany home directory"),
+    AP_INIT_TAKE1("SCAContribution", (const char*(*)())confContribution, NULL, ACCESS_CONF, "SCA contribution location"),
+    AP_INIT_TAKE1("SCAComposite", (const char*(*)())confComposite, NULL, ACCESS_CONF, "SCA composite location"),
+    {NULL}
+};
+
+int postConfig(apr_pool_t *p, apr_pool_t *plog, apr_pool_t *ptemp, server_rec *s) {
+   return OK;
+}
+
+void childInit(apr_pool_t* p, server_rec* svr_rec) {
+    ServerConf *conf = (ServerConf*)ap_get_module_config(svr_rec->module_config, &mod_tuscany_wiring);
+    if(conf == NULL) {
+        std::cerr << "[Tuscany] Due to one or more errors mod_tuscany_wiring loading failed. Causing apache to stop loading." << std::endl;
+        exit(APEXIT_CHILDFATAL);
+    }
+}
+
+void registerHooks(apr_pool_t *p) {
+    ap_hook_post_config(postConfig, NULL, NULL, APR_HOOK_MIDDLE);
+    ap_hook_child_init(childInit, NULL, NULL, APR_HOOK_MIDDLE);
+    ap_hook_handler(handler, NULL, NULL, APR_HOOK_MIDDLE);
+    ap_hook_translate_name(translate, NULL, NULL, APR_HOOK_FIRST);
+}
+
+}
+}
+}
+
+extern "C" {
+
+module AP_MODULE_DECLARE_DATA mod_tuscany_wiring = {
+    STANDARD20_MODULE_STUFF,
+    // dir config and merger
+    tuscany::httpd::makeDirConf<tuscany::server::modwiring::DirConf>, NULL,
+    // server config and merger
+    tuscany::httpd::makeServerConf<tuscany::server::modwiring::ServerConf>, NULL,
+    // commands and hooks
+    tuscany::server::modwiring::commands, tuscany::server::modwiring::registerHooks
+};
+
+}