How to write composite query in salesforce

Question

I have used Rest Api Code , i want to query from two different objects in single Http request,For that I am using composite Query in rest Api code

HttpRequest req = new HttpRequest();
req.setEndpoint('callout:Namedcredentialname/services/data/v39.0/query/composite');
req.setMethod('GET');
req.setbody({ 
        "compositeRequest" :[{
        "method" : "GET",
        "url" : "/services/data/v39.0/query/?q=SELECT+Id,MasterLabel,TotalLicenses,UsedLicenses,status+FROM+UserLicense",
        "referenceId" : "ref"                                
         },{
        "method" : "GET",
        "url" : "/services/data/v39.0/query/?q=SELECT+Id,name+FROM+organization",
        "referenceId" : "ref"}]});

        //Get SessionId
        string autho = 'Bearer '+userInfo.getSessionId();
        req.setHeader('Authorization', autho);

        //Get Response
        Http http = new Http();
        HTTPresponse res= http.send(req);
        string response = res.getBody();

How to construct req.body in composite Query of Rest api code? Getting error

Unrecognized symbol '"', which is not a valid Apex identifier I have modified with single quotes

req.setbody({
        'compositeRequest' :[{
        'method' : 'GET',
        'url' : '/services/data/v39.0/query/?q=SELECT+Id,MasterLabel,TotalLicenses,UsedLicenses,status+FROM+UserLicense',
        'referenceId' : 'refContact'                                
         },{
        'method' : 'GET',
        'url' : '/services/data/v39.0/query/?q=SELECT+Id,name+FROM+organization',
        'referenceId' : 'refContact'}]})

Compile Error: Expecting ')' but was: '{

req.setbody('{\"compositeRequest\" :[{
        \"method\" : \"GET\",
        \"url\" : \"/services/data/v39.0/query/?q=SELECT+Id+,MasterLabel+,TotalLicenses+,UsedLicenses+,+status+FROM+UserLicense\",
        \"referenceId\" : \"refContact\"                               
         },{
        \"method\" : \"GET\",
        \"url\" : \"/services/data/v39.0/query/?q=SELECT+Id+,name+FROM+organization\",
        \"referenceId\" : \"refContact\"}]}')

Illegal string literal: Line breaks are not allowed in string literals

Answer 1

Let's take a look at your request body:

req.setbody({ 
    "compositeRequest" :[{
    "method" : "GET",
    "url" : "/services/data/v39.0/query/?q=SELECT+Id,MasterLabel,TotalLicenses,UsedLicenses,status+FROM+UserLicense",
    "referenceId" : "ref"                                
     },{
    "method" : "GET",
    "url" : "/services/data/v39.0/query/?q=SELECT+Id,name+FROM+organization",
    "referenceId" : "ref"}]});

The documentation for HttpRequest.setBody tells us the following:

setBody(body)

Sets the contents of the body for this request.

Signature

public Void setBody(String body)

Parameters

body Type: String

Return Value

Type: Void

Usage

Limit: 6 MB for synchronous Apex or 12 MB for asynchronous Apex.

The HTTP request and response sizes count towards the total heap size.

Your request body is missing single quotes at the start and end (so it's not a string as-is). Not entirely sure how Salesforce is treating the open curly brace, but your error is being raised when Salesforce tries to parse the first double quote in "compositeRequest".

N.B. Strings cannot span multiple lines, so you'll need to put your entire JSON string on a single line, or concatenate each line using +.

+edit:

Your new error is because you haven't applied my answer correctly. The issue wasn't that you had double quotes, the issue was (and remains) that you aren't passing a string to the setBody() method (which expects a string).

// This is not a string
{"compositeRequest" :[{ ... }]}

// This is a string
// Notice how the entire thing is enclosed by single quotes (i.e. ')
'{"compositeRequest" :[{ ... }]}'

// String literals cannot span multiple lines
// The following is invalid and will result in an error
String s = 'one line,
two line,
red line,
blue line';

// You either need to put everything on a single line
String s = 'one line, two line, red line, blue line';

// Or concatenate with the + operator
String s = 'one line,'
+ ' two line,'
+ ' red line,'
+ ' blue line';

Answer 2

On top of what Derek has mentioned that you need to enclose your JSON in the request body within single quotes (that's how String is declared in Apex), you also need to fix your query. You will need to perform two things here:

• Fix your request body enclosing in single quotes. To provide a pointer, you need to construct your request body as below (notice that it starts with a single quote, ends with a single quote and that you use the forward slash to allow quotes in the body):

  req.setbody('{\"compositeRequest\" ...')';

• Fix your query as below. Notice the plus between the field names separated by comma. You need to put a plus sign to separate every item in your query

  SELECT+Id+,+MasterLabel+,+TotalLicenses+,+UsedLicenses+,+status+FROM+UserLicense