Workbench is one of widely used tool in Salesforce when it comes to exploring REST API of Salesforce. However I wanted to export REST API response in Binary format and therefore used cURL. cURL is open source command line library mostly used to test http request. It can be downloaded from here and official documentation about how to use cURL can be referred from here.
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 & email@example.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.