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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>
    
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    #include <fcntl.h>
    #include <sys/types.h>
    #include <sys/stat.h>
    #ifdef WIN32
    #include <io.h>
    #endif
    #include <stdio.h>
    
    
    struct per_session_data__post_demo {
    
    	struct lws_spa *spa;
    	char result[LWS_PRE + 500];
    
    	int result_len;
    
    
    	char filename[256];
    	long file_length;
    
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    	lws_filefd_type fd;
    
    };
    
    static const char * const param_names[] = {
    	"text",
    	"send",
    	"file",
    	"upload",
    };
    
    enum enum_param_names {
    	EPN_TEXT,
    	EPN_SEND,
    	EPN_FILE,
    	EPN_UPLOAD,
    
    static int
    file_upload_cb(void *data, const char *name, const char *filename,
    	       char *buf, int len, enum lws_spa_fileupload_states state)
    {
    	struct per_session_data__post_demo *pss =
    			(struct per_session_data__post_demo *)data;
    	int n;
    
    	switch (state) {
    	case LWS_UFS_OPEN:
    		strncpy(pss->filename, filename, sizeof(pss->filename) - 1);
    		/* we get the original filename in @filename arg, but for
    		 * simple demo use a fixed name so we don't have to deal with
    		 * attacks  */
    		pss->fd = open("/tmp/post-file",
    			       O_CREAT | O_TRUNC | O_RDWR, 0600);
    		break;
    	case LWS_UFS_FINAL_CONTENT:
    	case LWS_UFS_CONTENT:
    		if (len) {
    			pss->file_length += len;
    
    			/* if the file length is too big, drop it */
    			if (pss->file_length > 100000)
    				return 1;
    
    			n = write(pss->fd, buf, len);
    			lwsl_notice("%s: write %d says %d\n", __func__, len, n);
    		}
    		if (state == LWS_UFS_CONTENT)
    			break;
    		close(pss->fd);
    		pss->fd = LWS_INVALID_FILE;
    		break;
    	}
    
    	return 0;
    }
    
    
    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:
    
    		/* create the POST argument parser if not already existing */
    		if (!pss->spa) {
    			pss->spa = lws_spa_create(wsi, param_names,
    					ARRAY_SIZE(param_names), 1024,
    					file_upload_cb, pss);
    			if (!pss->spa)
    				return -1;
    
    			pss->filename[0] = '\0';
    			pss->file_length = 0;
    		}
    
    		/* let it parse the POST data */
    		if (lws_spa_process(pss->spa, in, len))
    			return -1;
    
    		break;
    
    	case LWS_CALLBACK_HTTP_BODY_COMPLETION:
    		lwsl_debug("LWS_CALLBACK_HTTP_BODY_COMPLETION\n");
    
    		/* call to inform no more payload data coming */
    		lws_spa_finalize(pss->spa);
    
    		p = (unsigned char *)pss->result + LWS_PRE;
    		end = p + sizeof(pss->result) - LWS_PRE - 1;
    		p += sprintf((char *)p,
    			"<html><body><h1>Form results (after urldecoding)</h1>"
    			"<table><tr><td>Name</td><td>Length</td><td>Value</td></tr>");
    
    		for (n = 0; n < ARRAY_SIZE(param_names); n++)
    			p += snprintf((char *)p, end - p,
    				    "<tr><td><b>%s</b></td><td>%d</td><td>%s</td></tr>",
    				    param_names[n],
    				    lws_spa_get_length(pss->spa, n),
    				    lws_spa_get_string(pss->spa, n));
    
    		p += snprintf((char *)p, end - p, "</table><br><b>filename:</b> %s, <b>length</b> %ld",
    				pss->filename, pss->file_length);
    
    		p += snprintf((char *)p, end - p, "</body></html>");
    		pss->result_len = p - (unsigned char *)(pss->result + LWS_PRE);
    
    
    		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;
    
    		lws_callback_on_writable(wsi);
    		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_DROP_PROTOCOL:
    		/* called when our wsi user_space is going to be destroyed */
    		if (pss->spa) {
    			lws_spa_destroy(pss->spa);
    			pss->spa = NULL;
    		}
    		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,
    	},
    };
    
    
    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;
    }
    
    
    destroy_protocol_post_demo(struct lws_context *context)
    {
    	return 0;
    }