使用 Stable Diffusion 和 TinyPNG 生成优化的文章特色图片

此 Persisted GraphQL query 使用 Stable Diffusion 生成式 AI，为没有特色图片的文章生成图片。

首先，它会检查文章是否已有特色图片。如果没有，则通过调用 Stable Diffusion 的生成式 AI 服务来创建一张。使用前需要提供 API 密钥。

由于生成式 AI 产生的图片未针对 Web 进行优化，该 query 还可以将新生成的图片发送至 TinyPNG 进行压缩。使用前同样需要提供 API 密钥。

最后，该 query 会使用该图片创建一个新的媒体项，并将其设置为文章的特色图片。

query InitializeVariables(
  $tinyPngAPIKey: String
)
  @configureWarningsOnExportingDuplicateVariable(enabled: false)
{
  isFeaturedImageMissing: _echo(value: false)
    @export(as: "isFeaturedImageMissing")
    @remove
 
  isPostTitleNotEmpty: _echo(value: false)
    @export(as: "isPostTitleNotEmpty")
    @remove
 
  generatedImageURL: _echo(value: null)
    @export(as: "generatedImageURL")
    @remove
 
  isImageGenerated: _echo(value: false)
    @export(as: "isImageGenerated")
    @remove
 
  mimeType: _echo(value: null)
    @export(as: "mimeType")
    @remove
 
  isMediaItemCreated: _echo(value: false)
    @export(as: "isMediaItemCreated")
    @remove
 
  useTinyPng: _notEmpty(value: $tinyPngAPIKey)
    @export(as: "useTinyPng")
    @remove
}
 
query ExportPostData(
  $postID: ID!
)
  @depends(on: "InitializeVariables")
{
  post(by: { id: $postID }, status: any) {
    hasFeaturedImage
    isFeaturedImageMissing: hasFeaturedImage
      @boolOpposite
      @export(as: "isFeaturedImageMissing")
    title
      @export(as: "postTitle")
    rawTitle
      @remove
    isPostTitleNotEmpty: _notEmpty(value: $__rawTitle)
      @export(as: "isPostTitleNotEmpty")
    mediaItemFilename: rawTitle
      @default(value: "untitled", condition: IS_EMPTY)
      @strLowerCase
      @strSubstr(offset: 0, length: 20)
      @export(as: "filename")
      @remove
  }
}
 
query GenerateImageUsingStableDiffusion(
  $stableDiffusionAPIKey: String!
  $width: Int! = 1024
  $height: Int! = 1024
)
  @depends(on: "ExportPostData")
  @include(if: $isFeaturedImageMissing)
  @include(if: $isPostTitleNotEmpty)
{
  stableDiffusionResponse: _sendJSONObjectItemHTTPRequest(input: {
    url: "https://stablediffusionapi.com/api/v3/text2img",
    method: POST,
    options: {
      json: {
        key: $stableDiffusionAPIKey
        prompt: $postTitle,
        width: $width
        height: $height
        samples: 1
      }
    }
  })
    @underJSONObjectProperty(by: { key: "output" })
      @underArrayItem(index: 0)
        @export(as: "generatedImageURL")
  
  stableDiffusionImageCaption: _sprintf(
    string: "Image created by Stable Diffusion using prompt: '%s'",
    values: [$postTitle]
  )
    @export(as: "imageCaption")
  
  stableDiffusionMediaItemFilename: _sprintf(
    string: "%s.png",
    values: [$filename]
  )
    @export(as: "filename")
}
 
query CheckIsImageGenerated
  @depends(on: "GenerateImageUsingStableDiffusion")
  @include(if: $isFeaturedImageMissing)
  @include(if: $isPostTitleNotEmpty)
{
  isImageGenerated: _notEmpty(value: $generatedImageURL)
    @export(as: "isImageGenerated")
}
 
query MaybeCompressGeneratedImage(
  $tinyPngAPIKey: String
)
  @depends(on: "CheckIsImageGenerated")
  @include(if: $isImageGenerated)
  @include(if: $useTinyPng)
{
  compressedImageResponse: _sendHTTPRequest(input: {
    url: "https://api.tinify.com/shrink",
    method: POST,
    options: {
      auth: {
        password: $tinyPngAPIKey
      },
      headers: [
        {
          name: "Content-Type",
          value: "application/json"
        }
      ],
      json: {
        source: {
          url: $generatedImageURL
        }
      }
    }
  }) {
    body
      @remove
    bodyJSONObject: _strDecodeJSONObject(string: $__body)
 
    mimeType: _objectProperty(
      object: $__bodyJSONObject
      by: { path: "output.type" }
    )
      @export(as: "mimeType")
 
    generatedImageURL: header(name: "Location")
      @export(as: "generatedImageURL")
  }
}
 
mutation CreateMediaItemFromGeneratedImage
  @depends(on: "MaybeCompressGeneratedImage")
  @include(if: $isImageGenerated)
{
  createMediaItem(input: {
    from: {
      url: {
        source: $generatedImageURL
        filename: $filename
      }
    }
    title: $postTitle
    caption: $imageCaption
    altText: $postTitle
    mimeType: $mimeType
  }) {
    mediaItemID
      @export(as: "mediaItemID")
    isMediaItemCreated: _notNull(value: $__mediaItemID)
      @export(as: "isMediaItemCreated")
      @remove
 
    status
    errors {
      __typename
      ...on ErrorPayload {
        message
      }
    }
    mediaItem {
      altText
      caption
      mimeType
      slug
      src
      title
    }
  }
}
 
mutation GenerateOptimizedPostFeaturedImageUsingStableDiffusion(
  $postID: ID!
)
  @depends(on: "CreateMediaItemFromGeneratedImage")
  @include(if: $isMediaItemCreated)
{
  setFeaturedImageOnCustomPost(input: {
    customPostID: $postID
    mediaItemBy: { id: $mediaItemID }
  }) {
    status
    errors {
      __typename
      ...on ErrorPayload {
        message
      }
    }
    customPost {
      __typename
      ...on CustomPost {
        featuredImage {
          id
          altText
          caption
          mimeType
          slug
          src
          title
        }
      }
    }
  }
}