To use cURL with Salesforce REST API, we will need to use username – password flow of OAuth2. To use OAuth2, we need to create connected App. You can check “Create Connected app” section of this post. You can enter any URL for callback or if you have already created any connected app in past, then it can be used. After creating connected app, note “Consumer key” and “Consumer Secret” somewhere.

create file “LoginInfo.txt” file which will have all required login information in URL encoded format

grant_type=password& client_id= 3MVG9iTxZANhwsdsdsdsdspr0Lu3QNRNKk4c2FejzTys5Mlp43UeSHBuhWWgRjEUyV6xE7N0GostjR3sRat & client_secret=21961212323233121943 & username=jitendra.zaa@demo.com & password=myPWDAndSecurityToken

make sure there is no space in above file. I have added some space for sake of readability.

grant_type=password informs Salesforce to use “Username and password” flow of OAuth2, We are also passing client_id, client_secret, username and password.

1. Login to Salsforce using cURL

Run below command to login into Salesforce

curl -X POST -d @LoginInfo.txt https://login.salesforce.com/services/oauth2/token

Output :

{"id":"https://login.salesforce.com/id/00D90000000YnViEAK/00590000000Gl5VAAS", "issued_at":"1437005678627", "token_type":"Bearer", "instance_url":"https://shivasoftdemo-dev-ed.my.salesforce.com", "signature":"RlUOj40dyd0bhSZPNIKqE7Jp7DpyXSKULEFaYolW/3I=", "access_token":"00D90000000YnVi!ARIAQB0fu5fjPy_ JClQ7B343ffdfRcPv0toe7QcotaZu1aWJnVmN2enCLAeUKBQVcnSvR3JjDz20 2LfRpGTRzaCdsds6lUBnaQ"}

Above output returned in JSON format is not readable so we can add header “PrettyPrint” in REST API request to return formatted json response.

2. Login to Salsforce using cURL with PrettyPrint option

new request will look like :

curl -X POST -d @LoginInfo.txt https://login.salesforce.com/services/oauth2/token -H "X-PrettyPrint:1"

Output :

{
  "id" : "https://login.salesforce.com/id/00D90000000YnViEAK/005900df000Gl5VAAS",
  "issued_at" : "1437005809464",
  "token_type" : "Bearer",
  "instance_url" : "https://shivasoftdemo-dev-ed.my.salesforce.com",
  "signature" : "3PD9nGTtpis23aWNP8IPtL3sYNuApFdfdd8eDa2Rc=",
  "access_token" : "00D90000000YnVi!ARIAQB0fu5fjPy_JClQ7BrkkyX3RcPvdfdaWJnVmN 2enCLAeUKBQVcnSvR3JjDz202LfRpGTRzaCmsC6lUBnaQ"
}

If login is success then we will get response as shown above. Extract “access_token” and “instance_url” from above response, as it will be used on every subsequent API calls.

As we received session id in form of “access_token”, we can use cURL exactly like workbench as shown in below example.

3. Example – Get information about all available REST API in Salesforce

curl -H "Authorization: Bearer 00D90000000YnVi!ARIAQBdfu5fjPy_JClQ7BrkkyX3RcPv0toe 7QcotaZu1aWJnVmN2enCLAeUKBQVcnSvR3JjDz202LfRpGTRzaCmsC6lUBnaQ" -H "X-PrettyPrint:1" https://shivasoftdemo-dev-ed.my.salesforce.com/services/data/v34.0/

Don’t forget to include Bearer attribute in double quotes as session id contains exclamation mark and it creates issue while sending request.

Output :

{
  "limits" : "/services/data/v34.0/limits",
  "sobjects" : "/services/data/v34.0/sobjects",
  "support" : "/services/data/v34.0/support",
  "connect" : "/services/data/v34.0/connect",
  "query" : "/services/data/v34.0/query",
  "theme" : "/services/data/v34.0/theme",
  "queryAll" : "/services/data/v34.0/queryAll",
  "nouns" : "/services/data/v34.0/nouns",
  "knowledgeManagement" : "/services/data/v34.0/knowledgeManagement",
  "tooling" : "/services/data/v34.0/tooling",
  "chatter" : "/services/data/v34.0/chatter",
  "analytics" : "/services/data/v34.0/analytics",
  "recent" : "/services/data/v34.0/recent",
  "composite" : "/services/data/v34.0/composite",
  "process" : "/services/data/v34.0/process",
  "licensing" : "/services/data/v34.0/licensing",
  "identity" : "https://login.salesforce.com/id/00D90000000YnViEAK/00590000000Gl5VAAS",
  "flexiPage" : "/services/data/v34.0/flexiPage",
  "search" : "/services/data/v34.0/search",
  "quickActions" : "/services/data/v34.0/quickActions",
  "wave" : "/services/data/v34.0/wave",
  "appMenu" : "/services/data/v34.0/appMenu",
  "compactLayouts" : "/services/data/v34.0/compactLayouts",
  "actions" : "/services/data/v34.0/actions",
  "tabs" : "/services/data/v34.0/tabs"
}

Making Salesforce REST API request without SessionId

Curl works like browser, If we try to access REST API directly from browser then we get below error

If we try to do same with cURL then we will get same error:

Try to access Visualforce page using cURL

To access Visualforce page in Salesforce, first we need to login to Salesforce. Once logged in, if we try to access Visualforce page even with valid session Id, we will not get proper output because of Salesforce security , it shows that it is checking for sfdc.app and navigator and tries to redirect to Login page.  It does not display expected output from Visualforce. It clearly seems that salesforce is using some sort of security to check valid request.

In same way, if we are logged in to curl previously and then try to access Visualforce using post method then salesforce tries to display form element with request forwarded from cURL. It does not display expected output from Visualforce. We can clearly see that how secure is salesforce and there is no way to break it.

First and foremost step is to add your Salesforce instance URL in Remote site settings. Once that is done, use below sample Apex code to call Salesforce REST API.

I am using API to get metadata information about Salesforce object however that can be replaced by any supported REST API of Salesforce.

//Make sure your Salesforce instance URL is added in remote site settings
String sfdcURL = URL.getSalesforceBaseUrl().toExternalForm(); 
String restAPIURL = sfdcURL + '/services/data/v29.0/sobjects/';  
  
HttpRequest httpRequest = new HttpRequest();  
httpRequest.setMethod('GET');   
httpRequest.setHeader('Authorization', 'OAuth ' + UserInfo.getSessionId());        
httpRequest.setHeader('Authorization', 'Bearer ' + UserInfo.getSessionID()); 
httpRequest.setEndpoint(restAPIURL);  
String response = '';
try {  
		 Http http = new Http();   
		 HttpResponse httpResponse = http.send(httpRequest);  
		 if (httpResponse.getStatusCode() == 200 ) {  
			   response = JSON.serializePretty( JSON.deserializeUntyped(httpResponse.getBody()) );  
		 } else {  
			   System.debug(' httpResponse ' + httpResponse.getBody() );  
			   throw new CalloutException( httpResponse.getBody() );  
		 }   
} catch( System.Exception e) {  
		 System.debug('ERROR: '+ e);  
		 throw e;  
}  
System.debug(' ** response ** : ' + response );  

Key aspect in above code is how session Id is used as a value in OAuth and Bearer headers.

In my words, Getting data from Other System or Same System using HTTP request is known as REST API.

If you know, how website works, you know REST API. Before REST API, there was SOAP request which needed lots of configuration and very tightly coupled. If you make any modification , you had to modify client side also by generating stubs / proxy classes again. There were many more disadvantages which got address by REST API. However, it doesn’t mean we don’t need SOAP.

Back to REST API, It is very simple to setup and almost any programming language can make HTTP request so very easy to get data from other source. Return type of REST API can be XML, Simple HTTP, JSON or any media like image. However, JSON is very popular response type amongst all.

In Past, I have already written one article demonstrating REST API usage.

How to use Salesforce REST API using JQuery in Visualforce ?

REST API Playground : I have created Simple Visualforce page, which demonstrates how to use REST API of Salesforce. It is written in Visualforce with the help of JQuery. You can study this code and play with it in your organization, you just need to copy and paste it.

You also need to add URL “http://cdnjs.cloudflare.com” in Remote Site Settings, so that salesforce will allow Visualforce page to get JQuery library from CDN.

Video Demo :

Complete Visualforce page :