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Polylang
PolylangPolylang

Polylang

Integration with the Polylang plugin (and also Polylang PRO).

The GraphQL schema is provided the fields to retrieve multilingual data.

Types Root/QueryRoot

Query the site metadata configured in Polylang.

FieldDescription
polylangDefaultLanguageDefault language on Polylang, or null if there are no languages enabled.
polylangLanguagesList of languages on Polylang.

Running this query:

{
  polylangDefaultLanguage {
    code
  }
  polylangLanguages {
    code
  }
}

...might produce:

{
  "data": {
    "polylangDefaultLanguage": {
      "code": "en"
    },
    "polylangLanguages": [
      {
        "code": "en"
      },
      {
        "code": "es"
      },
      {
        "code": "fr"
      }
    ]
  }
}

Types Post, Page, PostTag, PostCategory and Media

Query the language for the entity, and the IDs for the translations for that entity.

These types implement interface PolylangTranslatable. (Type Media does only when media support is enabled, via the Polylang settings.)

FieldDescription
polylangLanguageLanguage of the post or page, or null if no language was assigned (eg: Polylang was installed later on).
polylangTranslationLanguageIDsNodes for all the translation languages for the entity, as a JSON object with the language code as key and entity ID as value, or null if no language was assigned (eg: Polylang was installed later on).

Field polylangTranslationLanguageIDs provides the entity IDs for all the translations (i.e. post/page/category/tag/media). It accepts input includeSelf, to indicate if to include the queried entity's ID in the results (it's false by default), and inputs includeLanguages and excludeLanguages, to filter the included languages in the results.

Running this query:

{
  posts {
    __typename
    id
    title
    polylangLanguage {
      code
    }
    polylangTranslationLanguageIDs
    polylangTranslationLanguageIDsWithSelf: polylangTranslationLanguageIDs(filter: { includeSelf: true })
 
    categories {
      __typename
      id
      name
      polylangLanguage {
        code
      }
      polylangTranslationLanguageIDs
      polylangTranslationLanguageIDsWithSelf: polylangTranslationLanguageIDs(filter: { includeSelf: true })
    }
    
    tags {
      __typename
      id
      name
      polylangLanguage {
        code
      }
      polylangTranslationLanguageIDs
      polylangTranslationLanguageIDsWithSelf: polylangTranslationLanguageIDs(filter: { includeSelf: true })
    }
  }
 
  pages {
    __typename
    id
    title
    polylangLanguage {
      code
    }
    polylangTranslationLanguageIDs
    polylangTranslationLanguageIDsWithSelf: polylangTranslationLanguageIDs(filter: { includeSelf: true })
  }
 
  mediaItems {
    __typename
    id
    title
    polylangLanguage {
      code
    }
    polylangTranslationLanguageIDs
    polylangTranslationLanguageIDsWithSelf: polylangTranslationLanguageIDs(filter: { includeSelf: true })
  }
}

...might produce:

{
  "data": {
    "posts": [
      {
        "__typename": "Post",
        "id": 1668,
        "title": "Some post translated using Polylang",
        "polylangLanguage": {
          "code": "en"
        },
        "polylangTranslationLanguageIDs": {
          "fr": 1670,
          "es": 1672
        },
        "polylangTranslationLanguageIDsWithSelf": {
          "en": 1668,
          "fr": 1670,
          "es": 1672
        },
        "categories": [
          {
            "__typename": "PostCategory",
            "id": 61,
            "name": "Category for Polylang",
            "polylangLanguage": {
              "code": "en"
            },
            "polylangTranslationLanguageIDs": {
              "fr": 63,
              "es": 65
            },
            "polylangTranslationLanguageIDsWithSelf": {
              "en": 61,
              "fr": 63,
              "es": 65
            }
          }
        ],
        "tags": [
          {
            "__typename": "PostTag",
            "id": 67,
            "name": "Tag for Polylang",
            "polylangLanguage": {
              "code": "en"
            },
            "polylangTranslationLanguageIDs": {
              "fr": 69,
              "es": 71
            },
            "polylangTranslationLanguageIDsWithSelf": {
              "en": 67,
              "fr": 69,
              "es": 71
            }
          }
        ]
      }
    ],
    "pages": [
      {
        "__typename": "Page",
        "id": 1674,
        "title": "Some page translated using Polylang",
        "polylangLanguage": {
          "code": "en"
        },
        "polylangTranslationLanguageIDs": {
          "fr": 1676,
          "es": 1678
        },
        "polylangTranslationLanguageIDsWithSelf": {
          "en": 1674,
          "fr": 1676,
          "es": 1678
        }
      }
    ],
    "mediaItems": [
      {
        "__typename": "Media",
        "id": 40,
        "title": "Media-for-Polylang",
        "polylangLanguage": {
          "code": "en"
        },
        "polylangTranslationLanguageIDs": {
          "fr": 42,
          "es": 44
        },
        "polylangTranslationLanguageIDsWithSelf": {
          "en": 40,
          "fr": 42,
          "es": 44
        }
      }
    ]
  }
}

Types GenericCustomPost, GenericTag and GenericCategory

These types implement interface PolylangMaybeTranslatable.

GenericCustomPost is a type used to represent any custom post installed on the site, such as Portfolio, Event, Product, or other. Similarly, GenericTag and GenericCategory are used to represent their taxonomies.

Each of these CPTs and taxonomies can be defined to be translatable on the Polylang settings. Fields polylangLanguage and polylangTranslationLanguageIDs will then have the same behavior as for Post and the others (described above), and also return null if the entity's CPT or taxonomy is not configured to be translated.

In addition, field polylangIsTranslatable indicates if the CPT or taxonomy is configured to be translatable.

FieldDescription
polylangLanguageLanguage of the post or page, or null if no language was assigned (eg: Polylang was installed later on), or if the entity is not configured to be translated (via Polylang Settings).
polylangTranslationLanguageIDsNodes for all the translation languages for the entity, as a JSON object with the language code as key and entity ID as value, or null if no language was assigned (eg: Polylang was installed later on), or if the entity is not configured to be translated (via Polylang Settings).
polylangIsTranslatableIndicate if the entity can be translated.

Running this query:

{
  customPosts(filter: { customPostTypes: ["some-cpt", "another-cpt"] }) {
    __typename
    ...on GenericCustomPost {
      id
      title
      customPostType
      polylangIsTranslatable
      polylangLanguage {
        code
      }
      polylangTranslationLanguageIDs
      polylangTranslationLanguageIDsWithSelf: polylangTranslationLanguageIDs(filter: { includeSelf: true })
      
      categories(taxonomy: "some-category") {
        __typename
        ...on GenericCategory {
          id
          name
          polylangIsTranslatable
          polylangLanguage {
            code
          }
          polylangTranslationLanguageIDs
          polylangTranslationLanguageIDsWithSelf: polylangTranslationLanguageIDs(filter: { includeSelf: true })
        }
      }
      
      tags(taxonomy: "some-tag") {
        __typename
        ...on GenericTag {
          id
          name
          polylangIsTranslatable
          polylangLanguage {
            code
          }
          polylangTranslationLanguageIDs
          polylangTranslationLanguageIDsWithSelf: polylangTranslationLanguageIDs(filter: { includeSelf: true })
        }
      }
    }
  }
}

...might produce:

{
  "data": {
    "customPosts": [
      {
        "__typename": "GenericCustomPost",
        "id": 10,
        "title": "Some CPT that has Polylang translation enabled",
        "customPostType": "some-cpt",
        "polylangIsTranslatable": true,
        "polylangLanguage": {
          "code": "en"
        },
        "polylangTranslationLanguageIDs": {
          "fr": 12,
          "es": 14
        },
        "polylangTranslationLanguageIDsWithSelf": {
          "en": 10,
          "fr": 12,
          "es": 14
        },
        "categories": [
          {
            "__typename": "GenericCategory",
            "id": 30,
            "name": "Some Category for Polylang",
            "polylangIsTranslatable": true,
            "polylangLanguage": {
              "code": "en"
            },
            "polylangTranslationLanguageIDs": {
              "fr": 32,
              "es": 34
            },
            "polylangTranslationLanguageIDsWithSelf": {
              "en": 30,
              "fr": 32,
              "es": 34
            }
          }
        ],
        "tags": [
          {
            "__typename": "GenericTag",
            "id": 50,
            "name": "Some Tag for Polylang",
            "polylangIsTranslatable": true,
            "polylangLanguage": {
              "code": "en"
            },
            "polylangTranslationLanguageIDs": {
              "fr": 52,
              "es": 54
            },
            "polylangTranslationLanguageIDsWithSelf": {
              "en": 50,
              "fr": 52,
              "es": 54
            }
          }
        ]
      },
      {
        "__typename": "GenericCustomPost",
        "id": 20,
        "title": "Another CPT that does not have Polylang translation enabled",
        "customPostType": "another-cpt",
        "polylangIsTranslatable": false,
        "polylangLanguage": null,
        "polylangTranslationLanguageIDs": null,
        "polylangTranslationLanguageIDsWithSelf": null,
        "categories": [
          {
            "__typename": "GenericCategory",
            "id": 70,
            "name": "Category without support for Polylang",
            "polylangIsTranslatable": false,
            "polylangLanguage": null,
            "polylangTranslationLanguageIDs": null,
            "polylangTranslationLanguageIDsWithSelf": null
          }
        ],
        "tags": [
          {
            "__typename": "GenericTag",
            "id": 72,
            "name": "Tag without support for Polylang",
            "polylangIsTranslatable": false,
            "polylangLanguage": null,
            "polylangTranslationLanguageIDs": null,
            "polylangTranslationLanguageIDsWithSelf": null
          }
        ]
      }
    ]
  }
}

Mutations

The GraphQL schema is provided with mutations to:

  • Establish the language for custom posts, tags, categories, and media items, and
  • Define associations among them (i.e. indicate that a set of custom posts, tags, categories, or media items is a translation for each other).
MutationDescription
polylangSetCustomPostLanguageSet the language of the custom post.
polylangSetTaxonomyTermLanguageSet the language of the taxonomy term.
polylangSetMediaItemLanguageSet the language of the media item.
polylangSaveCustomPostTranslationAssociationSet the translation association for the custom post.
polylangSaveTaxonomyTermTranslationAssociationSet the translation association for the taxonomy term.
polylangSaveMediaItemTranslationAssociationSet the translation association for the media item.

For instance, the following query defines the language for 3 posts (to English, Spanish and French), and then defines that these 3 posts are a translation of each other:

mutation {
  post1: polylangSetCustomPostLanguage(input: {id: 1, languageBy: { code: "en" }}) {
    status
    errors {
      __typename
      ...on ErrorPayload {
        message
      }
    }
  }
  post2: polylangSetCustomPostLanguage(input: {id: 2, languageBy: { code: "es" }}) {
    status
    errors {
      __typename
      ...on ErrorPayload {
        message
      }
    }
  }
  post3: polylangSetCustomPostLanguage(input: {id: 3, languageBy: { code: "fr" }}) {
    status
    errors {
      __typename
      ...on ErrorPayload {
        message
      }
    }
  }
  polylangSaveCustomPostTranslationAssociation(input: {
    ids: [1, 2, 3]
  }) {
    status
    errors {
      __typename
      ...on ErrorPayload {
        message
      }
    }
  }
}

Filter data by language

We can provide the language to filter by when fetching data for:

  • Posts
  • Pages
  • Custom posts
  • Categories
  • Tags
  • Media items

The corresponding fields receive input polylangLanguageBy, and we can filter by code or locale, and by 1 or more than 1 language.

For instance, passing $languageCodes: ["es"] will fetch data in Spanish:

query FilterByLanguage($languageCodes: [String!])
{
  posts(filter: {
    polylangLanguagesBy: { codes: $languageCodes }
  }) {
    id
    title
  }
 
  pages(filter: {
    polylangLanguagesBy: { codes: $languageCodes }
  }) {
    id
    title
  }
 
  customPosts(filter: {
    customPostTypes: ["some-cpt"]
    polylangLanguagesBy: { codes: $languageCodes }
  }) {
    id
    title
  }
 
  postCategories(filter: {
    polylangLanguagesBy: { codes: $languageCodes }
  }) {
    id
    name
  }
 
  postTags(filter: {
    polylangLanguagesBy: { codes: $languageCodes }
  }) {
    id
    name
  }
 
  categories(
    taxonomy: "some-category"
    filter: { polylangLanguagesBy: { codes: $languageCodes } }
  ) {
    id
    name
  }
 
  tags(
    taxonomy: "some-tag"
    filter: { polylangLanguagesBy: { codes: $languageCodes } }
  ) {
    id
    name
  }
 
  mediaItems(filter: {
    polylangLanguagesBy: { codes: $languageCodes }
  }) {
    id
    title
  }
}