silverstripe-framework/docs/en/02_Developer_Guides/19_GraphQL/02_working_with_dataobjects/02_query_plugins.md

title	summary
DataObject query plugins	Learn about some of the useful goodies that come pre-packaged with DataObject queries

Working with DataObjects

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DataObject query plugins

This module has a plugin system that affords extensibility to queries, mutations, types, fields, and just about every other thread of the schema. Model types can define default plugins to include, and for DataObject queries, these include:

• filter
• sort
• paginateList
• inheritance
• canView (read, readOne)
• firstResult (readOne)

When the silverstripe/cms module is installed, a plugin known as getByLink is also added. Other modules, such as silverstripe-versioned may augment that list with even more.

The pagination plugin

The pagination plugin augments your queries in two main ways:

• Adding limit and offset arguments
• Wrapping the return type in a "connection" type with the following fields:
  • nodes: '[YourType]'
  • edges: '[{ node: YourType }]'
  • pageInfo: '{ hasNextPage: Boolean, hasPreviousPage: Boolean: totalCount: Int }'

Let's test it out:

query {
  readPages(limit: 10, offset: 20) {
    nodes {
      title
    }
    edges {
        node {
            title
        }
    }
    pageInfo {
        totalCount
        hasNextPage
        hasPrevPage
    }
}

[notice] If you're not familiar with the jargon of edges and node, don't worry too much about it for now. It's just a pretty well-established convention for pagination in GraphQL, mostly owing to its frequent use with cursor-based pagination, which isn't something we do in Silverstripe CMS. [/notice]

Disabling pagination

Just set it to false in the configuration.

app/_graphql/models.yml

MyProject\Models\ProductCategory:
  operations:
    read:
      plugins:
        paginateList: false

To disable pagination globally, use modelConfig:

app/_graphql/modelConfig.yml

DataObject:
  operations:
    read:
      plugins:
        paginateList: false

The filter plugin

The filter plugin (SilverStripe\GraphQL\Schema\DataObject\Plugin\QueryFilter) adds a special filter argument to the read and readOne operations.

query {
  readPages(
    filter: { title: { eq: "Blog" } }
  ) {
  nodes {
    title
    created
  }
}

In the above example, the eq is known as a comparator. There are several of these included with the the module, including:

• eq (exact match)
• ne (not equal)
• contains (fuzzy match)
• gt (greater than)
• lt (less than)
• gte (greater than or equal)
• lte (less than or equal)
• in (in a given list)
• startswith (starts with)
• endswith (ends with)

Example:

query {
  readPages (
    filter: {
      title: { ne: "Home" },
      created: { gt: "2020-06-01", lte: "2020-09-01" }
    }
  ) {
  nodes {
    title
    created
  }
}

[notice] While it is possible to filter using multiple comparators, segmenting them into disjunctive groups (e.g. "OR" and "AND" clauses) is not yet supported. [/notice]

Nested fields are supported by default:

query {
  readProductCategories(
    filter: {
      products: {
        reviews: {
          rating: { gt: 3 },
          comment: { contains: "awesome" },
          author: { ne: "Me" }
        }
      }
    }
  ) {
  nodes {
    title
  }
}

Filters are only querying against the database by default, it is not possible to filter by fields with custom resolvers.

Customising the filter fields

By default, all fields on the dataobject, including relationships, are included. To customise this, just add a fields config to the plugin definition:

app/_graphql/models.yml

MyProject\Models\ProductCategory:
  fields:
    title: true
    featured: true
  operations:
    read:
      plugins:
        filter:
          fields:
            title: true

Disabling the filter plugin

Just set it to false in the configuration.

app/_graphql/models.yml

MyProject\Models\ProductCategory:
  operations:
    read:
      plugins:
        filter: false

To disable filtering globally, use modelConfig:

app/_graphql/modelConfig.yml

DataObject:
  operations:
    read:
      plugins:
        filter: false

The sort plugin

The sort plugin (SilverStripe\GraphQL\Schema\DataObject\Plugin\QuerySort) adds a special sort argument to the read and readOne operations.

query {
  readPages (
    sort: { created: DESC }
  ) {
      nodes {
        title
        created
      }
  }
}

Nested fields are supported by default, but only for linear relationships (e.g has_one):

query {
  readProducts(
    sort: {
      primaryCategory: {
        lastEdited: DESC
      }
    }
  ) {
      nodes {
        title
      }
  }
}

Customising the sort fields

By default, all fields on the dataobject, including has_one relationships, are included. To customise this, just add a fields config to the plugin definition:

app/_graphql/models.yml

MyProject\Models\ProductCategory:
  fields:
    title: true
    featured: true
  operations:
    read:
      plugins:
        sort:
          fields:
            title: true

Disabling the sort plugin

Just set it to false in the configuration.

app/_graphql/models.yml

MyProject\Models\ProductCategory:
  operations:
    read:
      plugins:
        sort: false

To disable sort globally, use modelConfig:

app/_graphql/config.yml

modelConfig:
  DataObject:
    operations:
      read:
        plugins:
          sort: false

The getByLink plugin

When the silverstripe/cms module is installed (it is in most cases), a plugin called getByLink will ensure that queries that return a single DataObject model (e.g. readOne) get a new query argument called link (configurable on the field_name property of LinkablePlugin).

readOneSiteTree(link: "/about-us" ) {
  title
}

Further reading

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