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  •  * ws protocol handler plugin for "POST demo"
    
     *
     * Copyright (C) 2010-2016 Andy Green <andy@warmcat.com>
     *
     * This file is made available under the Creative Commons CC0 1.0
     * Universal Public Domain Dedication.
     *
     * The person who associated a work with this deed has dedicated
     * the work to the public domain by waiving all of his or her rights
     * to the work worldwide under copyright law, including all related
     * and neighboring rights, to the extent allowed by law. You can copy,
     * modify, distribute and perform the work, even for commercial purposes,
     * all without asking permission.
     *
     * These test plugins are intended to be adapted for use in your code, which
     * may be proprietary.  So unlike the library itself, they are licensed
     * Public Domain.
     */
    #include "../lib/libwebsockets.h"
    #include <string.h>
    
    struct per_session_data__post_demo {
    	char post_string[256];
    	char result[500 + LWS_PRE];
    	int result_len;
    };
    
    static int
    callback_post_demo(struct lws *wsi, enum lws_callback_reasons reason,
    		   void *user, void *in, size_t len)
    {
    	struct per_session_data__post_demo *pss =
    			(struct per_session_data__post_demo *)user;
    	unsigned char buffer[LWS_PRE + 512];
    	unsigned char *p, *start, *end;
    	int n;
    
    	switch (reason) {
    
    	case LWS_CALLBACK_HTTP_BODY:
    		lwsl_debug("LWS_CALLBACK_HTTP_BODY: len %d\n", (int)len);
    		strncpy(pss->post_string, in, sizeof (pss->post_string) -1);
    		pss->post_string[sizeof(pss->post_string) - 1] = '\0';
    
    		if (len < sizeof(pss->post_string) - 1)
    			pss->post_string[len] = '\0';
    		break;
    
    	case LWS_CALLBACK_HTTP_WRITEABLE:
    		lwsl_debug("LWS_CALLBACK_HTTP_WRITEABLE: sending %d\n", pss->result_len);
    		n = lws_write(wsi, (unsigned char *)pss->result + LWS_PRE,
    			      pss->result_len, LWS_WRITE_HTTP);
    		if (n < 0)
    			return 1;
    		goto try_to_reuse;
    
    	case LWS_CALLBACK_HTTP_BODY_COMPLETION:
    		lwsl_debug("LWS_CALLBACK_HTTP_BODY_COMPLETION\n");
    		/*
    		 * the whole of the sent body arrived,
    		 * respond to the client with a redirect to show the
    		 * results
    		 */
    		pss->result_len = sprintf((char *)pss->result + LWS_PRE,
    			    "<html><body><h1>Form results</h1>'%s'<br>"
    			    "</body></html>", pss->post_string);
    
    		p = buffer + LWS_PRE;
    		start = p;
    		end = p + sizeof(buffer) - LWS_PRE;
    
    		if (lws_add_http_header_status(wsi, 200, &p, end))
    			return 1;
    
    		if (lws_add_http_header_by_token(wsi, WSI_TOKEN_HTTP_CONTENT_TYPE,
    				(unsigned char *)"text/html", 9, &p, end))
    			return 1;
    		if (lws_add_http_header_content_length(wsi, pss->result_len, &p, end))
    			return 1;
    		if (lws_finalize_http_header(wsi, &p, end))
    			return 1;
    
    		n = lws_write(wsi, start, p - start, LWS_WRITE_HTTP_HEADERS);
    		if (n < 0)
    			return 1;
    
    		/*
    		 *  send the payload next time, in case would block after
    		 * headers
    		 */
    		lws_callback_on_writable(wsi);
    		break;
    
    	default:
    		break;
    	}
    
    	return 0;
    
    try_to_reuse:
    	if (lws_http_transaction_completed(wsi))
    		return -1;
    
    	return 0;
    }
    
    static const struct lws_protocols protocols[] = {
    	{
    		"protocol-post-demo",
    		callback_post_demo,
    		sizeof(struct per_session_data__post_demo),
    		1024,
    	},
    };
    
    LWS_VISIBLE int
    init_protocol_post_demo(struct lws_context *context,
    			struct lws_plugin_capability *c)
    {
    	if (c->api_magic != LWS_PLUGIN_API_MAGIC) {
    		lwsl_err("Plugin API %d, library API %d", LWS_PLUGIN_API_MAGIC,
    			 c->api_magic);
    		return 1;
    	}
    
    	c->protocols = protocols;
    	c->count_protocols = ARRAY_SIZE(protocols);
    	c->extensions = NULL;
    	c->count_extensions = 0;
    
    	return 0;
    }
    
    LWS_VISIBLE int
    destroy_protocol_post_demo(struct lws_context *context)
    {
    	return 0;
    }