ExpressionAttributeValues must not be empty in graphQL with Gatsby

Description

I’m using Gatsby with the below plugin.

"gatsby": "^2.21.0",
"gatsby-source-graphql": "^2.7.6",

When I use GraphQL, I got this error. I researched a solution, I couldn’t any hints.

ExpressionAttributeValues must not be empty (Service: DynamoDb, Status Code: 400, Request ID: 8A2PS0BPLA5RB1869L21ONB0NJVV4KQNSO5AEMVJF66Q9ASUAAJG, Extended Request ID: null)

The GraphQL is below.

###[./src/pages/profile.js]

.....
export const query = graphql`
  query GetSingleProfile($slug: String) {
    DynamoDB {
      listBlrUsermatchs(filter: {slug: {eq: $slug}}) {
        items {
          id
          imgUrl
          imgUrlS3
          kinds
          languagesSpoken
          location
          name
          .......
        }
      }
    }
  }
`
.....

I have below in gatsby-node.js.

###[gatsby-node.js.]

  const usermatches = await graphql(`
   {
    usermatches: DynamoDB {
      listBlrUsermatchs {
        items {
          slug
          state
          city
          category
        }
      }
    }
  }
  `)

  usermatches.data.usermatches.listBlrUsermatchs.items.forEach(data => {
    // Make Category
    var category = '';
    data.category.map((p) => {
      category = category + '-' + p;
    })
    const state = data.state[0].replace(' ', '-').toLowerCase();
    const city = data.city.replace(' ', '-').toLowerCase();

    category = category.substring(1);
    const uri = category + '/' + state + '/' + city + '/' + data.slug;
    createPage({
      path: `/${uri}`,
      component: path.resolve(`./src/pages/profile.js`),
      context: {
        slug: data.slug
      },
    });
  });

I want to pash a ‘slug’ that is defined in getsby-node.js tho, it might cause the problem. When I use a fixed value (like a ‘programer’ ) instead of $slug in profile.js, it goes well. And also, although I get the error, the program works.

[vladar]

Thank you for opening this, @uekyo

The problem is that you’ve placed your template in src/pages folder: https://gitlab.com/kyo.ueda/bug-repro-gatsby-slug/-/blob/master/src/pages/places.js

Gatsby creates pages for all files in src/pages folder automatically. But it executes queries from those files without any variables. And that’s why you see this error. If you move your template file from src/pages/places.js to src/templates/places.js and update the path in createPages API it works as expected.

We’re marking this issue as answered and closing it for now but please feel free to reopen this and comment if you would like to continue this discussion. We hope we managed to help and thank you for using Gatsby! 💜

[vladar]

Have you tried running the same query against your remote GraphQL endpoint directly (with slug as a variable):

    query DynamoDB($slug: String) {
      listBlrUsermatchs(filter: {slug: {eq: $slug}}) {
        items {
          id
          imgUrl
          imgUrlS3
          kinds
          languagesSpoken
          location
          name
        }
      }
    }

I am a bit suspicious about the filter part here: listBlrUsermatchs(filter: {slug: {eq: $slug}}). It looks like a Gatsby filter.

Also to clarify: the error you’ve posted comes from your remote GraphQL API not from Gatsby, that’s why I am asking.