如何构建GitHub APIv4的Golang查询以获取指定Release

我在使用githubv4库拉取GitHub仓库的指定Release时遇到了问题：下面的代码始终返回空值，但目标仓库jacobtomlinson/gha-find-replace确实存在v3版本。

有问题的代码：

var releaseQ struct {
  Repository struct {
    Release struct {
        Author githubv4.String
    } `graphql:"release(tagName:$tagName)"`
  } `graphql:"repository(owner:$repositoryOwner,name:$repositoryName)"`
}
variables = map[string]interface{}{
    "repositoryOwner": githubv4.String("jacobtomlinson"),
    "repositoryName":  githubv4.String("gha-find-replace"),
    "tagName":         githubv4.String("v3"),
}
err = client.Query(context.Background(), &releaseQ, variables)
if err != nil {
    fmt.Println("Query returned nothing")
}
fmt.Println("author:", releaseQ.Repository.Release.Author)

我已经成功实现了以下功能：

• 获取仓库描述（代码可正常返回结果）：

var repoDescriptionQ struct {
  Repository struct {
    Description string
  } `graphql:"repository(owner: \"jacobtomlinson\", name: \"gha-find-replace\")"`
}

• 获取Issue的反应内容（代码可正常获取结果）：

variables := map[string]interface{}{
  "repositoryOwner": githubv4.String("jacobtomlinson"),
  "repositoryName":  githubv4.String("gha-find-replace"),
  "issueNumber":     githubv4.Int(55),
  "reactionContent": githubv4.ReactionContentThumbsDown,
}
var reactionQ struct {
Repository struct {
    Issue struct {
        ID        githubv4.ID
        Reactions struct {
            ViewerHasReacted githubv4.Boolean
        } `graphql:"reactions(content:$reactionContent)"`
    } `graphql:"issue(number:$issueNumber)"`
} `graphql:"repository(owner:$repositoryOwner,name:$repositoryName)"`
}

解决方法 #

问题出在Release结构体的Author字段定义上：GitHub GraphQL API里，Release的author是一个User对象，而非单纯的字符串类型。你直接将Author映射为githubv4.String，导致字段无法正确解析，最终返回空值。

修改代码中的Release结构体，正确映射author的子字段即可：

var releaseQ struct {
  Repository struct {
    Release struct {
        Author struct {
            Login githubv4.String // 取User对象的login字段
        } `graphql:"author"`
    } `graphql:"release(tagName:$tagName)"`
  } `graphql:"repository(owner:$repositoryOwner,name:$repositoryName)"`
}

输出时需要访问嵌套的Login字段：

fmt.Println("author:", releaseQ.Repository.Release.Author.Login)

另外，建议优化错误提示，方便定位问题：

if err != nil {
    fmt.Printf("查询失败：%v\n", err)
}

内容的提问来源于stack exchange，提问作者John Set