HTTP Communication on Tizen (Tizen Ver. 2.3)

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1 HTTP Communication on Tizen (Tizen Ver. 2.3) Spring 2015 Soo Dong Kim, Ph.D. Professor, Department of Computer Science Software Engineering Laboratory Soongsil University Office Mobile

2 Unit 7-1. Overview of HTTP Communication 2

3 What is HTTP Communication? An application protocol for distributed, collaborative, hypermedia information systems Foundation of data communication for the World Wide Web Request Response 3

4 GET HTTP Methods To request a representation of the specified resource POST To submit data to be processed to the identified resource To submit files to a server PUT To upload a representation of the specified resource DELETE To delete the specified resource 4

5 REST (Representational State Transfer) A software architecture style consisting of guidelines and best practices for creating scalable web services To communicate over the HTTP(Hypertext Transfer Protocol) with the same HTTP verbs GET POST PUT DELETE 5

6 Usage of HTTP Methods in REST Used as CRUD functions in manipulating data Refer to all of the major functions in manipulating data Operation Create Retrieve Update Delete HTTP POST GET PUT DELETE 6

7 Unit 7-2. HTTP on Tizen Web App (Tizen Ver. 2.3) 7

8 Two Ways for HTTP Communication Synchronous Communication To use Form tags Asynchronous Communication To use Ajax Most commonly used in Tizen Web Application 8

9 Privilege Settings To allow to use specific features To add the privilege, config.xml > Privileges > Add 9

10 Policy Settings To allow an Tizen Web app to access a specific URL To add the policy, Network URL: * Allow Subdomain: True config.xml > Policy > Add 10

11 Form Tag Used to create an HTML form for user input To reload other web pages Key Attributes Action A string containing the URL to which the request is sent Method Usage The HTTP method to use for the request <form action="demo_form.asp" method="get"> name: <input type="text" name= Gildong Hong"><br> <input type="submit" value="submit"> </form> 11

12 AJAX (Asynchronous JavaScript and XML) A group of interrelated Web development techniques used on the client-side to create asynchronous Web applications Not a new programming language, but a new way to use existing standards To exchange data with a server, and update parts of a web page without reloading the whole page 12

13 jquery.ajax() jquery Methods for Ajax To perform an asynchronous HTTP (Ajax) request jquery.get() To load data from the server using a HTTP GET request jquery.post() To load data from the server using a HTTP POST request 13

14 jquery.ajax(url [, settings]) Url jquery.ajax() (1) A string containing the URL to which the request is sent Settings A set of key/value pairs that configure the Ajax request 14

15 jquery.ajax() (2) Setting Keys Method The HTTP method to use for the request GET, POST, PUT Data Data to be sent to the server Datatype The type of data that you're expecting back from the server XML, JSON, HTML Success A function to be called if the request succeeds Error A function to be called if the request fails 15

16 Example jquery.ajax() (3) $("#bt-ajax").click(function() { $.ajax({ url : " method : "GET", crossdomain : true, datatype : "json", success : function(res) { $("#p-ajax-res").html(json.stringify(res)); }, error : function(err) { $("#p-ajax-res").html(json.stringify(err)); } }); }); 16

17 jquery.get(url [, Settings]) Url jquery.get() (1) A string containing the URL to which the request is sent Settings A set of key/value pairs that configure the Ajax request A shorthand Ajax function $.get({ url: url, data: data, success: success, datatype: datatype }); = $.ajax({ url: url, method: GET data: data, success: success, datatype: datatype }); 17

18 jquery.get() (2) Setting Keys Data A plain object or string that is sent to the server with the request Success A function to be called if the request succeeds DataType A function to be called if the request fails 18

19 jquery.post(url [, Settings]) Url jquery.post() (1) A string containing the URL to which the request is sent Settings A set of key/value pairs that configure the Ajax request A shorthand Ajax function $.post({ url: url, data: data, success: success, datatype: datatype }); = $.ajax({ url: url, method: POST data: data, success: success, datatype: datatype }); 19

20 jquery.post() (2) Setting Keys Data A plain object or string that is sent to the server with the request Success A function to be called if the request succeeds DataType A function to be called if the request fails 20

21 Unit 7-3. HTTP on Tizen Native App (Tizen Ver. 2.3) 21

22 Prerequisite Required Header curl.h Required Privilege 22

23 curl_easy_init() Key Functions curl_slist_append() curl_easy_setopt () curl_easy_perform () curl_formadd () curl_easy_cleanup() 23

24 curl_easy_init() To return a handle used as input to other functions in the Curl interface Return CURL handle on success, otherwise NULL value 24

25 curl_slist_append() To append a specified string to a linked list of strings To create header information for a HTTP request To create commands for a FTP request Parameters Type Name Description struct curl_slist* list Pointer of a linked list of string const char* string The string value assigned to the linked list Return A new list pointer, otherwise NULL pointer 25

26 curl_easy_setopt() To set options for a curl easy handle Parameters Type Name Description CURL * handle Curl handle CURLoption option Option for defining Curl s behavior void parameter parameter Key options Option Name CURLOPT_URL CURLOPT_WRITEFUNCTION CURLOPT_WRITEDATA CURLOPT_POST Description To define URL To define callback for returned data To define data pointer to pass to the write callback To define HTTP method as a POST Return 0 on success, otherwise non-zero value 26

27 curl_easy_perform () To transfer data as described in the options Parameters Type Name Description CURL * handle Curl handle Return 0 on success, otherwise non-zero value 27

curl_formadd () To append sections when building a multipart/formdata HTTP POST Parameters Type Name Description Curl_httppost * firstitem Curl handle Curl_httppost lastitem Option for defining Curl

28 curl_formadd () To append sections when building a multipart/formdata HTTP POST Parameters Type Name Description Curl_httppost * firstitem Curl handle Curl_httppost lastitem Option for defining Curl s behavior N/A Returns 0 on success, otherwise non-zero value Usages /*<input type= file, name= sendfile >*/ curl_formadd(&formpost, &lastptr, CURLFORM_COPYNAME, "sendfile", CURLFORM_FILE, "postit2.c", CURLFORM_END) 28

29 To end a libcurl easy handle Parameters curl_easy_cleanup() Type Name Description CURL * handle Curl handle Return None 29

30 Example (1) To retrieve JSON through HTTP request A struct for response data typedef struct curlresponsedata { char *response; //Response Data size_t size; //Data Size } CURL_RES_DATA; A function to initiate the struct void init_curl_responsedata(curl_res_data *res) { res->size = 0; res->response = malloc(res->size + 1); if (res->response == NULL) { dlog_print(dlog_info, "CALL_HTTP_REQUEST", "Allocation failed"); } } res->response[0] = '\0'; 30

31 Example (2) To retrieve JSON through HTTP request (cont d) A function to write retrieved data to the struct size_t curl_write_function(void *ptr, size_t size, size_t nmemb, CURL_RES_DATA *res) { size_t newlen = res->size + size * nmemb; res->response = realloc(res->response, newlen + 1); if (res->response == NULL) { dlog_print(dlog_info, "CALL_HTTP_REQUEST", "Allocation failed"); } //Copies response data to the structure memcpy(res->response + res->size, ptr, size * nmemb); res->response[newlen] = '\0'; res->size = newlen; return size * nmemb; } 31

32 Example (3) To retrieve JSON through HTTP request (cont d) To request HTTP request void call_http_request() { CURLcode res; CURL_RES_DATA res_data; char* jsonurl= " init_curl_responsedata(&res_data); // Initiates Curl handle curl = curl_easy_init(); if (curl) { // Initiates HTTP header struct curl_slist *headers = NULL; curl_slist_append(headers, "Accept: application/json"); curl_slist_append(headers, "Content-Type: application/json"); // Sets options curl_easy_setopt(curl, CURLOPT_URL, jsonurl); curl_easy_setopt(curl, CURLOPT_HTTPHEADER, headers); curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, curl_write_function); curl_easy_setopt(curl, CURLOPT_WRITEDATA, &res_data); } // Sends HTTP request curl_easy_perform(curl); free(res_data.response); curl_easy_cleanup(curl); } 32

33 Thank You! 33

HTTP Communication on Tizen

HTTP Communication on Tizen Spring 2015 Soo Dong Kim, Ph.D. Professor, Department of Computer Science Software Engineering Laboratory Soongsil University Office 02-820-0909 Mobile 010-7392-2220 sdkim777@gmail.com