By using AWS re:Post, you agree to the Terms of Use
/GraphQL DynamoDb filter List field/

GraphQL DynamoDb filter List field

0

I'm trying to use a graphQL API using AWS Amplify to list books that i've stored in DynamoDB filtered on a field that is a List type.

Schema

id: ID!
title: String
authorId: String
genre: [String]
...
}
I'm doing this:

API.graphql(graphqlOperation(listBooks, {
filter: {
genre: {
contains: category,
}
},
}))
But the only books being returned are the books with a single element and that element matches the category, for example when the category is "History" this will match

a list of {S: "History"}

but this will not match

a list of { "S" : "History" }, { "S" : "Politics and Social Sciences" }

My ModelBookFilterInput is this:

input ModelBookFilterInput {
id: ModelIDInput
genre: ModelStringInput
...
}
And the ModelStringInput has the contains: String attribute on it so it looks like it supports this.

I'm not sure what i'm doing wrong, any input appreciated.

Edited by: JesusGarcia94 on Aug 18, 2020 8:44 PM

Edited by: JesusGarcia94 on Aug 18, 2020 8:45 PM

Edited by: JesusGarcia94 on Aug 18, 2020 8:45 PM

Edited by: JesusGarcia94 on Aug 18, 2020 8:46 PM

1 Answers
0

It turns out I was neglecting to use the nextToken in the payload. the query will only look at 10 elements at a time by default so it's the dev's responsiblity to continue querying until they have enough matching results

Example of method to use nextToken:

/**

  • @desc Recursively fetch all items in a list query using nextToken
  • @param {Object} query The query object from cda-graphql in use.
  • @param {Object} variables The variables to pass to query.
  • @returns {Array} Array of all items received from queries.
    */
    import { API, graphqlOperation } from 'aws-amplify';

async function fetchItemsNextToken({ query, variables, limit}) {
const results = [];
while (results.length < limit) {
const { data } = await API.graphql(graphqlOperation(query, variables));
const key = Object.keys(data).find(k => k.includes('list'));
const res = data[key]; // res = { items: [], nextToken: '' }

    results.push(...res.items);  
    if (!res.nextToken) break;  

    // eslint-disable-next-line no-param-reassign  
    variables.nextToken = res.nextToken;  
}  
return new Promise((resolve, reject) => {  
    resolve(results);  
});  

}

export default fetchItemsNextToken;

answered 2 years ago

You are not logged in. Log in to post an answer.

A good answer clearly answers the question and provides constructive feedback and encourages professional growth in the question asker.

Guidelines for Answering Questions