Fetch many-to-many relation items with REST API

Question

In Parse I've two classes with a many-to-many relation, for example Products and its ProductImages. I've created in the class Products a relation with ProductImages and all work fine with querying and updating. There is limited documentation on many-to-many relation on Parse.

How to query all the Products with respective ProductImages data (Rest API Call) ?

Expected Response will be like this:

{
"name": "Apples",
"productImages": [
  {
"imagePath":"",
"videoPath":""
  }, {
"imagePath":"",
"videoPath":""
  }
]
}

Answer 1

There is no endpoint in the REST api to query both classes at the same time, but you can write a cloud code function to do that and retrieve all the data that you need with a single request. I'd do something like this:

Parse.Cloud.define('getProductsAndImages', async req => {
  const productsQuery = new Parse.Query('Product');
  const products = await productsQuery.find();
  return Promise.all(products.map(async product => ({
    ...product.toJSON(),
    productImagesObjs: await product.get('productImages').query().find()
  })));
});

Then you can call the function using the REST API like this:

curl -X POST \
  -H "X-Parse-Application-Id: ${APPLICATION_ID}" \
  -H "X-Parse-REST-API-Key: ${REST_API_KEY}" \
  -H "Content-Type: application/json" \
  -d '{}' \
  https://server.address.com/parse/functions/getProductsAndImages