This patch adds a RESTful HTTP interface to Asterisk.

The API itself is documented using Swagger, a lightweight mechanism for
documenting RESTful API's using JSON. This allows us to use swagger-ui
to provide executable documentation for the API, generate client
bindings in different languages, and generate a lot of the boilerplate
code for implementing the RESTful bindings. The API docs live in the
rest-api/ directory.

The RESTful bindings are generated from the Swagger API docs using a set
of Mustache templates.  The code generator is written in Python, and
uses Pystache. Pystache has no dependencies, and be installed easily
using pip. Code generation code lives in rest-api-templates/.

The generated code reduces a lot of boilerplate when it comes to
handling HTTP requests. It also helps us have greater consistency in the
REST API.

(closes issue ASTERISK-20891)
Review: https://reviewboard.asterisk.org/r/2376/

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@386232 65c4cc65-6c06-0410-ace0-fbb531ad65f3

rest-api-templates/stasis_http_resource.h.mustache

@@ -0,0 +1,68 @@
+{{#api_declaration}}
+/*
+ * Asterisk -- An open source telephony toolkit.
+ *
+ * {{{copyright}}}
+ *
+ * {{{author}}}
+ *
+ * See http://www.asterisk.org for more information about
+ * the Asterisk project. Please do not directly contact
+ * any of the maintainers of this project for assistance;
+ * the project provides a web site, mailing lists and IRC
+ * channels for your use.
+ *
+ * This program is free software, distributed under the terms of
+ * the GNU General Public License Version 2. See the LICENSE file
+ * at the top of the source tree.
+ */
+
+/*! \file
+ *
+ * \brief Generated file - declares stubs to be implemented in
+ * res/stasis_http/resource_{{name}}.c
+ *
+ * {{{description}}}
+ *
+ * \author {{{author}}}
+ */
+
+/*
+{{> do-not-edit}}
+ * This file is generated by a mustache template. Please see the original
+ * template in rest-api-templates/stasis_http_resource.h.mustache
+ */
+
+#ifndef _ASTERISK_RESOURCE_{{name_caps}}_H
+#define _ASTERISK_RESOURCE_{{name_caps}}_H
+
+#include "asterisk/stasis_http.h"
+
+{{#apis}}
+{{#operations}}
+/*! \brief Argument struct for stasis_http_{{c_nickname}}() */
+struct ast_{{c_nickname}}_args {
+{{#parameters}}
+{{#description}}
+	/*! \brief {{{description}}} */
+{{/description}}
+	{{c_data_type}}{{c_space}}{{c_name}};
+{{/parameters}}
+};
+/*!
+ * \brief {{summary}}
+{{#notes}}
+ *
+ * {{{notes}}}
+{{/notes}}
+ *
+ * \param headers HTTP headers
+ * \param args Swagger parameters
+ * \param[out] response HTTP response
+ */
+void stasis_http_{{c_nickname}}(struct ast_variable *headers, struct ast_{{c_nickname}}_args *args, struct stasis_http_response *response);
+{{/operations}}
+{{/apis}}
+
+#endif /* _ASTERISK_RESOURCE_{{name_caps}}_H */
+{{/api_declaration}}