openwrt下和云端通讯的例程,

秒速五厘米 2022-04-10 09:56 205阅读 0赞

[openwrt][][下和云端通讯的例程][openwrt]  
ibcurl

官方文档请参考这里 [http://curl.haxx.se/libcurl/c/curl\_easy\_setopt.html][http_curl.haxx.se_libcurl_c_curl_easy_setopt.html]  
  
刚接触 libcurl的时候, 自然的想到按照常规的思路来连接云端: 先连接Web, 再发送请求, 然后等待接受返回数据.  
这样思路的代码如下

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1.  /\*\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-  
    
2.  名称: http\_cloud\_curl\_simple.c  
    
3.  功能: 利用libcurl的API顺序实现云端通讯, 未利用回调机制  
    
4.  \-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\*/  
    
5.  \#include <stdio.h>  
    
6.  \#include <stdlib.h>  
    
7.  \#include <string.h>  
    
8.  \#include <curl/curl.h>  
    
9.  \#include <assert.h>  
    
10.   
    
11. \#include "../http\_cloud.h"  
    
12.   
    
13. \#define DBG printf  
    
14.   
    
15. //\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-  
    
16. static void get\_local\_time(char \*pc\_str)  
    
17. \{  
    
18. time\_t now;  
    
19. struct tm \*timenow;  
    
20.   
    
21. assert(pc\_str != NULL);  
    
22.   
    
23. time(&now);  
    
24. timenow = localtime(&now);  
    
25. sprintf(pc\_str, "%04d-%02d-%02dT%02d:%02d:%02d", timenow\->tm\_year\+1900, timenow\->tm\_mon\+1, timenow\->tm\_mday,  
    
26. timenow\->tm\_hour, timenow\->tm\_min, timenow\->tm\_sec);  
    
27. \}  
    
28.   
    
29. /\* Auxiliary function that waits on the socket. \*/  
    
30. static int wait\_on\_socket(curl\_socket\_t sockfd, int for\_recv, long timeout\_ms)  
    
31. \{  
    
32. struct timeval tv;  
    
33. fd\_set infd, outfd, errfd;  
    
34. int res;  
    
35.   
    
36. tv.tv\_sec = timeout\_ms / 1000;  
    
37. tv.tv\_usec= (timeout\_ms % 1000) \* 1000;  
    
38.   
    
39. FD\_ZERO(&infd);  
    
40. FD\_ZERO(&outfd);  
    
41. FD\_ZERO(&errfd);  
    
42.   
    
43. FD\_SET(sockfd, &errfd); /\* always check for error \*/  
    
44.   
    
45. if(for\_recv) \{  
    
46. FD\_SET(sockfd, &infd);  
    
47. \}  
    
48. else \{  
    
49. FD\_SET(sockfd, &outfd);  
    
50. \}  
    
51.   
    
52. /\* select() returns the number of signalled sockets or \-1 \*/  
    
53. res = select(sockfd \+ 1, &infd, &outfd, &errfd, &tv);  
    
54. return res;  
    
55. \}  
    
56.   
    
57. static char connect\_cloud(char \*pc\_ret, const char \*host\_addr, const int portno, const char \*request)  
    
58. \{  
    
59. CURL \*curl;  
    
60. CURLcode res;  
    
61. /\* Minimalistic http request \*/  
    
62. //const char \*request = "GET / HTTP/1.0\\r\\nHost: example.com\\r\\n\\r\\n";  
    
63. //char request\[1024\] = "";  
    
64. curl\_socket\_t sockfd; /\* socket \*/  
    
65. long sockextr;  
    
66. size\_t iolen;  
    
67. curl\_off\_t nread;  
    
68. int iLen = 0;  
    
69. char cRet = 0;  
    
70.   
    
71. assert((pc\_ret != NULL) && (host\_addr != NULL) && (request != NULL));  
    
72.   
    
73. //curl\_global\_init(CURL\_GLOBAL\_DEFAULT);  
    
74. curl = curl\_easy\_init();  
    
75. if (!curl) return 0;  
    
76.   
    
77. //curl\_easy\_setopt(curl, CURLOPT\_URL, "http://example.com");  
    
78. curl\_easy\_setopt(curl, CURLOPT\_URL, host\_addr);  
    
79. /\* Do not do the transfer \- only connect to host \*/  
    
80. curl\_easy\_setopt(curl, CURLOPT\_CONNECT\_ONLY, 1L);  
    
81. res = curl\_easy\_perform(curl);  
    
82. if(CURLE\_OK != res) \{  
    
83. printf("Error: %s\\n", strerror(res));  
    
84. return \-1;  
    
85. \}  
    
86.   
    
87. /\* Extract the socket from the curl handle \- we'll need it for waiting.  
    
88. \* Note that this API takes a pointer to a 'long' while we use  
    
89. \* curl\_socket\_t for sockets otherwise.  
    
90. \*/  
    
91. res = curl\_easy\_getinfo(curl, CURLINFO\_LASTSOCKET, &sockextr);  
    
92. if(CURLE\_OK != res) \{  
    
93. printf("Error: %s\\n", curl\_easy\_strerror(res));  
    
94. return \-2;  
    
95. \}  
    
96.   
    
97. sockfd = sockextr;  
    
98. /\* wait for the socket to become ready for sending \*/  
    
99. if(!wait\_on\_socket(sockfd, 0, 60000L)) \{  
    
100. printf("Error: timeout.\\n");  
    
101. return \-3;  
    
102. \}  
    
103.   
    
104. /\* Send the request. Real applications should check the iolen  
    
105. \* to see if all the request has been sent \*/  
    
106. res = curl\_easy\_send(curl, request, strlen(request), &iolen);  
    
107. if(CURLE\_OK != res) \{  
    
108. printf("Error: %s\\n", curl\_easy\_strerror(res));  
    
109. return \-4;  
    
110. \}  
    
111.   
    
112. /\* read the response \*/  
    
113. char buf\[1024\];  
    
114. while(1) \{  
    
115. wait\_on\_socket(sockfd, 1, 60000L);  
    
116. res = curl\_easy\_recv(curl, buf, 1024, &iolen);  
    
117.   
    
118. if(CURLE\_OK != res)  
    
119. break;  
    
120.   
    
121. nread = (curl\_off\_t)iolen;  
    
122. \}  
    
123. buf\[nread\] = '\\0';  
    
124. DBG("Received (%" CURL\_FORMAT\_CURL\_OFF\_T "), %s\\n", nread, buf);  
    
125.   
    
126. /\* always cleanup \*/  
    
127. curl\_easy\_cleanup(curl);  
    
128.   
    
129. pc\_ret = strstr(buf, "\\r\\n\\r\\n");  
    
130. if (pc\_ret) \{  
    
131. pc\_ret \+= 4;  
    
132. DBG("ret = %s\\n", pc\_ret);  
    
133. \}  
    
134.   
    
135. return 1;  
    
136. \}  
    
137.   
    
138. \#if (YEELINK == 1)  
    
139. int yeelink\_create\_data(const int device\_id, const int sensor\_id, const float device\_value)  
    
140. \{  
    
141. char pc\_ret\[200\], request\[1024\], pc\_json\[100\], pc\_time\[30\], pc\_host\_file\[100\], pc\_header\[100\], ret;  
    
142. int len;  
    
143.   
    
144. sprintf(pc\_host\_file, "v1.0/device/%d/sensor/%d/datapoints", device\_id, sensor\_id);  
    
145. sprintf(pc\_header, "U-ApiKey: %s", YEELINK\_API\_KEY);  
    
146.   
    
147. get\_local\_time(pc\_time);  
    
148. sprintf(pc\_json, "\{\\"timestamp\\":\\"%s\\",\\"value\\":%.2f\}", pc\_time, device\_value);  
    
149. len = strlen(pc\_json);  
    
150.   
    
151. sprintf(request, "POST /%s HTTP/1.1\\r\\nHost: %s\\r\\nAccept: \*/\*\\r\\n%s\\r\\nContent-Length: %d\\r\\nContent-Type: application/x-www-form-urlencoded\\r\\nConnection: Close\\r\\n\\r\\n%s\\r\\n",  
    
152. pc\_host\_file, YEELINK\_HOST, pc\_header, len, pc\_json);  
    
153. DBG("request = %s\\n", request);  
    
154.   
    
155. ret = connect\_cloud(pc\_ret, YEELINK\_HOST, YEELINK\_PORT, request);  
    
156.   
    
157. return(ret);  
    
158. \}  
    
159. \#endif  
    
160.   
    
161. \#if (LEWEI50 == 1)  
    
162. //curl \-\-request POST http://www.lewei50.com/api/V1/Gateway/UpdateSensors/01 \-\-data "\[\{\\"Name\\":\\"T1\\",\\"Value\\":\\"23.08\\"\}\]" \-\-header "userkey:36be8ff22f794f1e8a0bee3336eef237"  
    
163. int lewei50\_create\_data(const char \*device\_id, const float device\_value)  
    
164. \{  
    
165. char pc\_ret\[200\], request\[1024\], pc\_json\[100\], pc\_header\[100\], ret;  
    
166. int len;  
    
167.   
    
168. assert(device\_id != NULL);  
    
169.   
    
170. sprintf(pc\_header, "userkey: %s", LEWEI50\_USER\_KEY);  
    
171. sprintf(pc\_json, "\[\{\\"Name\\":\\"%s\\",\\"Value\\":\\"%.2f\\"\}\]", device\_id, device\_value);  
    
172. len = strlen(pc\_json);  
    
173.   
    
174. sprintf(request, "POST /%s HTTP/1.1\\r\\nHost: %s\\r\\nAccept: \*/\*\\r\\n%s\\r\\nContent-Length: %d\\r\\nContent-Type: application/x-www-form-urlencoded\\r\\nConnection: Close\\r\\n\\r\\n%s\\r\\n",  
    
175. LEWEI50\_HOST\_FILE, LEWEI50\_HOST, pc\_header, len, pc\_json);  
    
176. DBG("request = %s\\n", request);  
    
177.   
    
178. ret = connect\_cloud(pc\_ret, LEWEI50\_HOST, LEWEI50\_PORT, request);  
    
179.   
    
180. return(ret);  
    
181. \}  
    
182. \#endif  
    
183.   
    
184. //\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-  
    
185. int main(void)  
    
186. \{  
    
187. float f\_value = 15.02;  
    
188. int i\_tmp;  
    
189.   
    
190. time\_t t;  
    
191. srand((unsigned)time(&t)); //初始化随机种子, 否则随机数不随机  
    
192.   
    
193. i\_tmp = rand();  
    
194. i\_tmp \-= (i\_tmp >> 4 << 4);  
    
195. f\_value \+= i\_tmp;  
    
196.   
    
197. \#if (YEELINK == 1)  
    
198. yeelink\_create\_data(YEELINK\_DEVICE\_ID, YEELINK\_SENSOR\_ID, f\_value);  
    
199. \#endif  
    
200.   
    
201. \#if (LEWEI50 == 1)  
    
202. lewei50\_create\_data(LEWEI50\_DEVICE\_ID, f\_value);  
    
203. \#endif  
    
204.   
    
205. return 1;  
    
206. \}

Makefile: 注意openwrt的连接参数要多加的, 为了这几个字母, 折腾了好长时间

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1.  OPENWRT = 1  
    
2.    
    
3.  ifeq ($(OPENWRT), 1)  
    
4.  CC = ~/OpenWrt\-SDK\-ar71xx\-for\-linux\-i486\-gcc\-4.6\-linaro\_uClibc\-0.9.33.2/staging\_dir/toolchain\-mips\_r2\_gcc\-4.6\-linaro\_uClibc\-0.9.33.2/bin/mips\-openwrt\-linux\-gcc  
    
5.  CFLAGS \+= \-I ~/openwrt\-lib/include \-L ~/openwrt\-lib/lib  
    
6.  LFLAGS \+= \-lcurl \-lcrypto \-lz \-lssl  
    
7.    
    
8.  else  
    
9.  CC = gcc  
    
10. LFLAGS \+= \-lcurl  
    
11. endif  
    
12.   
    
13. CFLAGS \+= \-Wall \-O2  
    
14. \#CFLAGS \+= \-g  
    
15.   
    
16. \#可执行文件名和相关的obj文件  
    
17. APP\_BINARY = http\_cloud  
    
18. SRCS \+= http\_cloud\_curl\_simple.c  
    
19. OBJS = $(SRCS:.c=.o)  
    
20.   
    
21. all: APP\_FILE  
    
22.   
    
23. APP\_FILE: $(OBJS)  
    
24. $(CC) $(CFLAGS) $(OBJS) \-o $(APP\_BINARY) $(LFLAGS)  
    
25.   
    
26. .PHONY: clean  
    
27. clean:  
    
28. @echo "cleanning project"  
    
29. $(RM) \*.a $(OBJS) \*~ \*.so \*.lo $(APP\_BINARY)  
    
30. @echo "clean completed"

openwrt下的运行结果如下  
root@OpenWrt:/xutest\# ./http\_cloud\_libcurl  
yeelini ret = HTTP/1.1 200 OK  
Server: nginx/1.1.19  
Date: Thu, 07 Nov 2013 00:56:56 GMT  
Content-Type: text/html  
Transfer-Encoding: chunked  
Connection: close  
X-Powered-By: PHP/5.3.10-1ubuntu3.6  
Set-Cookie: CAKEPHP=dfvacsdpb8ls802dulnt695kk2; expires=Fri, 15-Nov-2013 08:56:56 GMT; path=/  
P3P: CP="NOI ADM DEV PSAi COM NAV OUR OTRo STP IND DEM"  
  
lewei50 ret = HTTP/1.1 200 OK  
Date: Thu, 07 Nov 2013 00:56:56 GMT  
Content-Type: application/json; charset=utf-8  
Content-Length: 44  
Connection: close  
Cache-Control: private  
Set-Cookie: SERVERID=a4a5b2bbca16d8c8b2ba6d5b6e55f36e|1383785816|1383785816;Path=/  
  
\{"Successful":true,"Message":"Successful. "\}  
  
root@OpenWrt:/xutest\#

--------------------

这仅仅是libcurl最最简单的应用, 本着'师夷长技以制夷'的原则, 继续看官方文档中.....

[openwrt]: http://blog.chinaunix.net/uid-27194309-id-3979680.html
[http_curl.haxx.se_libcurl_c_curl_easy_setopt.html]: http://curl.haxx.se/libcurl/c/curl_easy_setopt.html