Les 29: Een bericht importeren van een andere WordPress-site
Deze tutorial-les laat zien hoe je WordPress-sites gesynchroniseerd kunt houden door een bericht van een WordPress-site te importeren naar je lokale WordPress-site.
GraphQL-query om een bericht te importeren van een andere WordPress-site
De onderstaande GraphQL-query verbindt zich met het GraphQL-eindpunt van een upstream-website, haalt de gegevens op van een specifiek bericht en importeert het lokaal. De Gato GraphQL-plugin (gratis versie) moet ook op de upstream-website geïnstalleerd zijn.
(Als Gato GraphQL niet geïnstalleerd is op de upstream-site, kan de query aangepast worden om verbinding te maken met de WP REST API-eindpunten ervan.)
Alle bronnen waarnaar in het bericht verwezen wordt, moeten lokaal bestaan:
- De auteur
- De uitgelichte afbeelding (indien aanwezig)
- De categorieën
- (Tags ook, maar als deze nog niet bestaan, worden ze samen met het bericht aangemaakt, dus dat is geen probleem)
Als gemeenschappelijke identificator voor bronnen tussen de upstream- en lokale sites gebruiken we:
- Slugs voor categorieën, tags en media-items
- Gebruikersnamen voor gebruikers
Als een van de bronnen niet bestaat op de lokale site, geeft de GraphQL-query een fout en stopt het importeren.
query InitializeDynamicVariables
@configureWarningsOnExportingDuplicateVariable(enabled: false)
{
initVariablesWithFalse: _echo(value: false)
@export(as: "requestProducedErrors")
@export(as: "responseHasErrors")
@export(as: "postIsMissing")
@export(as: "postHasAuthor")
@export(as: "postHasFeaturedImage")
@export(as: "postHasCategories")
@export(as: "postHasTags")
@remove
initVariablesWithNull: _echo(value: null)
@export(as: "existingAuthorUsername")
@export(as: "existingFeaturedImageSlug")
@export(as: "featuredImageMutationInput")
@remove
initVariablesWithEmptyArray: _echo(value: [])
@export(as: "existingCategorySlugs")
@export(as: "existingTagSlugs")
@remove
}
query CheckIfPostExistsLocally($postSlug: String!)
@depends(on: "InitializeDynamicVariables")
{
localPost: post(
by: { slug: $postSlug }
status: any
) {
id
}
postAlreadyExists: _notNull(value: $__localPost)
@export(as: "postAlreadyExists")
}
query FailIfPostAlreadyExistsLocally($postSlug: String!)
@depends(on: "CheckIfPostExistsLocally")
@include(if: $postAlreadyExists)
{
errorMessage: _sprintf(
string: "Post with slug '%s' already exists locally",
values: [$postSlug]
) @remove
_fail(
message: $__errorMessage
data: {
slug: $postSlug
}
) @remove
createPost: _echo(value: null)
}
query ConnectToGraphQLAPI(
$upstreamServerGraphQLEndpointURL: String!
$postSlug: String!
)
@depends(on: "FailIfPostAlreadyExistsLocally")
@skip(if: $postAlreadyExists)
{
externalData: _sendGraphQLHTTPRequest(input:{
endpoint: $upstreamServerGraphQLEndpointURL,
query: """
query GetPost($postSlug: String!) {
post(by: { slug: $postSlug }) {
id
slug
rawTitle
rawContent
rawExcerpt
author {
id
username
}
featuredImage {
id
slug
}
categories {
id
slug
}
tags {
id
slug
}
}
}
""",
variables: [
{
name: "postSlug",
value: $postSlug
}
]
})
@export(as: "externalData")
requestProducedErrors: _isNull(value: $__externalData)
@export(as: "requestProducedErrors")
@remove
}
query ValidateResponse
@depends(on: "ConnectToGraphQLAPI")
@skip(if: $postAlreadyExists)
@skip(if: $requestProducedErrors)
{
responseHasErrors: _propertyIsSetInJSONObject(
object: $externalData
by: {
key: "errors"
}
)
@export(as: "responseHasErrors")
@remove
postExists: _propertyIsSetInJSONObject(
object: $externalData
by: {
path: "data.post"
}
)
@remove
postIsMissing: _not(value: $__postExists)
@export(as: "postIsMissing")
@remove
}
query FailIfResponseHasErrors
@depends(on: "ValidateResponse")
@skip(if: $postAlreadyExists)
@skip(if: $requestProducedErrors)
@skip(if: $postIsMissing)
@include(if: $responseHasErrors)
{
errors: _objectProperty(
object: $externalData,
by: {
key: "errors"
}
) @remove
_fail(
message: "Executing the GraphQL query against the upstream webserver produced error(s)"
data: {
errors: $__errors
}
) @remove
createPost: _echo(value: null)
}
query FailIfPostNotExists($postSlug: String!)
@depends(on: "FailIfResponseHasErrors")
@skip(if: $requestProducedErrors)
@include(if: $postIsMissing)
{
errorMessage: _sprintf(
string: "There is no post with slug '%s' in the origin",
values: [$postSlug]
) @remove
_fail(
message: $__errorMessage
data: {
slug: $postSlug
}
) @remove
createPost: _echo(value: null)
}
query ExportInputs
@depends(on: "FailIfPostNotExists")
@skip(if: $postAlreadyExists)
@skip(if: $requestProducedErrors)
@skip(if: $responseHasErrors)
@skip(if: $postIsMissing)
{
postData: _objectProperty(
object: $externalData,
by: { path: "data.post" }
) @remove
postTitle: _objectProperty(
object: $__postData,
by: { key: "rawTitle" }
)
@export(as: "postTitle")
@remove
postContent: _objectProperty(
object: $__postData,
by: { key: "rawContent" }
)
@export(as: "postContent")
@remove
postExcerpt: _objectProperty(
object: $__postData,
by: { key: "rawExcerpt" }
)
@export(as: "postExcerpt")
@remove
postAuthorUsername: _objectProperty(
object: $__postData,
by: { key: "author" }
)
@passOnwards(
as: "author"
)
@applyField(
name: "_notNull",
arguments: {
value: $author
},
passOnwardsAs: "hasAuthor"
)
@if(condition: $hasAuthor)
@applyField(
name: "_objectProperty",
arguments: {
object: $author,
by: { key: "username" }
},
setResultInResponse: true
)
@export(as: "postAuthorUsername")
@remove
postHasAuthor: _notNull(
value: $__postAuthorUsername
)
@export(as: "postHasAuthor")
@remove
postFeaturedImageSlug: _objectProperty(
object: $__postData,
by: { key: "featuredImage" }
)
@passOnwards(
as: "featuredImage"
)
@applyField(
name: "_notNull",
arguments: {
value: $featuredImage
},
passOnwardsAs: "hasFeaturedImage"
)
@if(condition: $hasFeaturedImage)
@applyField(
name: "_objectProperty",
arguments: {
object: $featuredImage,
by: { key: "slug" }
},
setResultInResponse: true
)
@export(as: "postFeaturedImageSlug")
@remove
postHasFeaturedImage: _notNull(
value: $__postFeaturedImageSlug
)
@export(as: "postHasFeaturedImage")
@remove
postCategorySlugs: _objectProperty(
object: $__postData,
by: { key: "categories" }
)
@underEachArrayItem(
passValueOnwardsAs: "category"
)
@applyField(
name: "_objectProperty"
arguments: {
object: $category,
by: {
key: "slug"
}
}
setResultInResponse: true
)
@export(as: "postCategorySlugs")
@remove
postHasCategories: _notEmpty(
value: $__postCategorySlugs
)
@export(as: "postHasCategories")
@remove
postTagSlugs: _objectProperty(
object: $__postData,
by: { key: "tags" }
)
@underEachArrayItem(
passValueOnwardsAs: "tag"
)
@applyField(
name: "_objectProperty"
arguments: {
object: $tag,
by: {
key: "slug"
}
}
setResultInResponse: true
)
@export(as: "postTagSlugs")
@remove
postHasTags: _notEmpty(
value: $__postTagSlugs
)
@export(as: "postHasTags")
@remove
}
query ExportExistingResources
@depends(on: "ExportInputs")
@skip(if: $postAlreadyExists)
@skip(if: $requestProducedErrors)
@skip(if: $responseHasErrors)
@skip(if: $postIsMissing)
{
existingAuthorByUsername: user(by: { username: $postAuthorUsername })
@include(if: $postHasAuthor)
{
id
username @export(as: "existingAuthorUsername")
}
existingFeaturedImageBySlug: mediaItem(by: { slug: $postFeaturedImageSlug })
@include(if: $postHasFeaturedImage)
{
id
slug @export(as: "existingFeaturedImageSlug")
}
existingCategoriesBySlug: postCategories(filter: { slugs: $postCategorySlugs })
@include(if: $postHasCategories)
{
id
slug @export(as: "existingCategorySlugs", type: LIST)
}
existingTagsBySlug: postTags(filter: { slugs: $postTagSlugs })
@include(if: $postHasTags)
{
id
slug @export(as: "existingTagSlugs", type: LIST)
}
}
query ExportMissingResources
@depends(on: "ExportExistingResources")
@skip(if: $postAlreadyExists)
@skip(if: $requestProducedErrors)
@skip(if: $responseHasErrors)
@skip(if: $postIsMissing)
{
isAuthorMissing: _notEquals(
value1: $postAuthorUsername,
value2: $existingAuthorUsername
) @export(as: "isAuthorMissing")
isFeaturedImageMissing: _notEquals(
value1: $postFeaturedImageSlug,
value2: $existingFeaturedImageSlug
) @export(as: "isFeaturedImageMissing")
missingCategorySlugs: _arrayDiff(
arrays: [$postCategorySlugs, $existingCategorySlugs]
) @export(as: "missingCategorySlugs")
areCategoriesMissing: _notEmpty(
value: $__missingCategorySlugs
) @export(as: "areCategoriesMissing")
# missingTagSlugs: _arrayDiff(
# arrays: [$postTagSlugs, $existingTagSlugs]
# ) @export(as: "missingTagSlugs")
# areTagsMissing: _notEmpty(
# value: $__missingTagSlugs
# ) @export(as: "areTagsMissing")
isAnyResourceMissing: _or(
values: [
$__isAuthorMissing,
$__isFeaturedImageMissing,
$__areCategoriesMissing,
# $__areTagsMissing,
]
) @export(as: "isAnyResourceMissing")
}
query FailIfAnyResourceIsMissing
@depends(on: "ExportMissingResources")
@skip(if: $postAlreadyExists)
@skip(if: $requestProducedErrors)
@skip(if: $postIsMissing)
@skip(if: $responseHasErrors)
@include(if: $isAnyResourceMissing)
{
performingValidations: id
@if(condition: $isAuthorMissing)
@fail(
message: "Author is missing in local site"
data: {
missingAuthorByUsername: $postAuthorUsername
}
condition: ALWAYS
)
@if(condition: $isFeaturedImageMissing)
@fail(
message: "Featured image is missing in local site"
data: {
missingFeaturedImageBySlug: $postFeaturedImageSlug
}
condition: ALWAYS
)
@if(condition: $areCategoriesMissing)
@fail(
message: "Categories are missing in local site"
data: {
missingCategoriesBySlug: $missingCategorySlugs
}
condition: ALWAYS
)
# @if(condition: $areTagsMissing)
# @fail(
# message: "Tags are missing in local site"
# data: {
# missingTagBySlug: $missingTagSlugs
# }
# condition: ALWAYS
# )
createPost: _echo(value: null)
}
query ExportMutationInputs
@depends(on: "FailIfAnyResourceIsMissing")
@skip(if: $postAlreadyExists)
@skip(if: $requestProducedErrors)
@skip(if: $responseHasErrors)
@skip(if: $postIsMissing)
@skip(if: $isAnyResourceMissing)
{
featuredImageMutationInput: _echo(value: {
slug: $postFeaturedImageSlug
})
@include(if: $postHasFeaturedImage)
@export(as: "featuredImageMutationInput")
@remove
}
mutation ImportPost(
$postSlug: String!
)
@depends(on: "ExportMutationInputs")
@skip(if: $postAlreadyExists)
@skip(if: $requestProducedErrors)
@skip(if: $responseHasErrors)
@skip(if: $postIsMissing)
@skip(if: $isAnyResourceMissing)
{
createPost(input: {
status: draft,
slug: $postSlug
title: $postTitle
contentAs: {
html: $postContent
},
excerpt: $postExcerpt
authorBy: {
username: $postAuthorUsername
},
featuredImageBy: $featuredImageMutationInput,
categoriesBy: {
slugs: $postCategorySlugs
},
tagsBy: {
slugs: $postTagSlugs
}
}) {
status
errors {
__typename
...on ErrorPayload {
message
}
}
post {
id
date
status
slug
title
content
excerpt
author {
id
username
}
featuredImage {
id
slug
}
categories {
id
slug
}
tags {
id
slug
}
}
}
}(Zoals we in eerdere tutorial-lessen hebben gezien) We gebruiken de Field to Input-functie (met de syntaxis $__field) om de opgeloste waarde van een veld door te geven aan een aangrenzend veld.
Als we de opgeloste waarde van een veld aan een directive moeten doorgeven, moeten we in plaats daarvan de directive @passOnwards gebruiken (die eveneens geleverd wordt door de Field to Input-extensie).
Deze query:
{
posts {
id
hasComments
notHasComments: _not(value: $__hasComments)
}
}...is equivalent aan deze query:
{
posts {
id
hasComments
notHasComments: hasComments
@passOnwards(as: "postHasComments")
@applyField(
name: "_not"
arguments: {
value: $postHasComments
},
setResultInResponse: true
)
}
}@passOnwards is handig om een berekening uit te voeren op de waarde van een veld. In de bovenstaande GraphQL-query wordt het bijvoorbeeld gebruikt om te controleren of de eigenschap user niet null is, voordat de eigenschap username eruit wordt gehaald (en de veldwaarde ermee wordt overschreven):
postAuthorUsername: _objectProperty(
object: $__postData,
by: { key: "author" }
)
@passOnwards(
as: "author"
)
@applyField(
name: "_notNull",
arguments: {
value: $author
},
passOnwardsAs: "hasAuthor"
)
@if(condition: $hasAuthor)
@applyField(
name: "_objectProperty",
arguments: {
object: $author,
by: { key: "username" }
},
setResultInResponse: true
)
@export(as: "postAuthorUsername")
@remove[WIP] Automatisch ontbrekende bronnen importeren
Het Gato GraphQL-schema moet uitgebreid worden met mutaties om:
Dit is werk in uitvoering. Zodra deze mutaties ondersteund worden, kan de GraphQL-query elk van de ontbrekende bronnen automatisch importeren.