Pelajaran 29: Mengimpor postingan dari situs WordPress lain
Pelajaran tutorial ini mendemonstrasikan cara menjaga situs WordPress tetap sinkron, dengan mengimpor postingan dari suatu situs WordPress ke situs WordPress lokal kita.
Query GraphQL untuk mengimpor postingan dari situs WordPress lain
Query GraphQL di bawah ini terhubung ke endpoint GraphQL situs web upstream, mengambil data untuk postingan tertentu, dan mengimpornya secara lokal. Plugin Gato GraphQL (versi gratis) juga harus diinstal di situs web upstream.
(Jika Gato GraphQL tidak diinstal di situs upstream, query dapat diadaptasi untuk terhubung ke endpoint WP REST API-nya.)
Sumber daya yang direferensikan dalam postingan harus semuanya ada secara lokal:
- Penulis
- Gambar unggulan (jika ada)
- Kategori
- (Tag juga, namun jika belum ada, tag akan dibuat bersama dengan postingan, sehingga tidak menjadi masalah)
Sebagai pengenal umum untuk sumber daya antara situs upstream dan lokal, kita menggunakan:
- Slug untuk kategori, tag, dan item media
- Username untuk pengguna
Jika ada sumber daya yang tidak ada di situs lokal, query GraphQL mencetak pesan kesalahan dan menghentikan impor.
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
}
}
}
}(Seperti yang telah kita lihat pada pelajaran tutorial sebelumnya) Kita menggunakan fitur Field to Input (dengan sintaks $__field) untuk meneruskan nilai yang telah di-resolve dari suatu field ke field yang bersebelahan.
Ketika kita perlu meneruskan nilai yang telah di-resolve dari suatu field ke sebuah directive, kita harus menggunakan directive @passOnwards sebagai gantinya (yang juga disediakan oleh ekstensi Field to Input).
Query ini:
{
posts {
id
hasComments
notHasComments: _not(value: $__hasComments)
}
}...setara dengan query ini:
{
posts {
id
hasComments
notHasComments: hasComments
@passOnwards(as: "postHasComments")
@applyField(
name: "_not"
arguments: {
value: $postHasComments
},
setResultInResponse: true
)
}
}@passOnwards berguna untuk menghasilkan komputasi pada nilai field. Misalnya, dalam query GraphQL di atas, directive ini digunakan untuk memeriksa apakah properti user bukan null, sebelum mengekstrak properti username-nya (dan mengganti nilai field dengan nilai tersebut):
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] Mengimpor sumber daya yang hilang secara otomatis
Skema Gato GraphQL harus ditingkatkan dengan mutasi untuk:
Ini adalah pekerjaan yang sedang dalam proses. Setelah mutasi-mutasi ini didukung, kita dapat membuat query GraphQL mengimpor setiap sumber daya yang hilang secara otomatis.