Fun with C client for PiCloud's REST API
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Join For FreeI was playing around with PiCloud’s REST API and had a bit of fun writing a C client for it. Now, why C? Well, because one of the reasons they provide a REST API is for your non-Python programs to easily access your Python code on PiCloud.
What I did is simple: I published the square_func using PiCloud’s documentation. Then I used libcurl’s C Interface to replicate the curl statements provided in the documentation. I have written the client in two parts: client1.c and client2.c. client1.c
invokes the published function, hence gets the Job ID. client2.c then
uses this jobID to get the result. Here are the source codes:
/*client1.c*/ /* This part of the client invokes the REST API of PiCloud and retrieves the Job ID http://docs.picloud.com/rest.html#invoking-functions */ #include <stdio.h> #include <curl/curl.h> int main(void) { CURL *curl; /* Make sure you set this appropriately*/ char *url="https://api.picloud.com/r/3222/square_func/"; CURLcode res; curl = curl_easy_init(); if(curl) { /* First set the URL that is about to receive our POST. This URL can just as well be a https:// URL if that is what should receive the data. */ curl_easy_setopt(curl, CURLOPT_URL, url); /* Specify the user/pass */ curl_easy_setopt(curl,CURLOPT_USERPWD,"apikey:secretkey"); /* Now specify the POST data */ curl_easy_setopt(curl, CURLOPT_POSTFIELDS, "x=5"); /* For HTTPS */ curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, 0L); /* Perform the request, res will get the return code */ res = curl_easy_perform(curl); printf("\nResult of Operation:: %d\n", res); /* always cleanup */ curl_easy_cleanup(curl); } return 0; }
/*client2.c*/ /* This part of the client retrieves the result given the job ID as the argument*/ #include <stdio.h> #include <stdlib.h> #include <curl/curl.h> int main(int argc, char *argv[]) { CURL *curl; char url[80]; CURLcode res; if (argc==1) { printf("Usage: ./client2 <jid>\n"); exit(0); } strcpy(url,"https://api.picloud.com/job/result/?jid="); strcat(url,argv[1]); curl = curl_easy_init(); if(curl) { /* First set the URL that is about to receive our POST. This URL can just as well be a https:// URL if that is what should receive the data. */ curl_easy_setopt(curl, CURLOPT_URL, url); /* Specify the user/pass */ curl_easy_setopt(curl,CURLOPT_USERPWD,"apikey:secretkey"); /* for HTTPS */ curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, 0L); /* Perform the request, res will get the return code */ res = curl_easy_perform(curl); printf("\nResult of Operation:: %d\n", res); /* always cleanup */ curl_easy_cleanup(curl); } return 0; }
Working
[gene@zion tmp]$ ./client1
{“jid”: 57, “version”: “0.1″}
Result of Operation:: 0
[gene@zion tmp]$ ./client2 57
{“version”: “0.1″, “result”: 25}
Result of Operation:: 0
Hope it works for you. PiCloud is fun!
Source: http://echorand.me/2012/01/27/picloud-and-rest-api-with-c-client/
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