pydantic进阶用法示例详解

from pydantic import BaseModel, Field

# 定义数据模型
class Project(BaseModel):
    url: str = Field(...)
    title: str = Field(...)
    content: str = Field(...)
    company: List[Dict] = Field(default=[])
    industry: str = Field(...)

# project_data均为接口返回的数据，加数据演示

# 之前的代码
project_data = {
    "url": "https://www.baidu.com",
    "title": "百度一下，你就知道",
}
project = Project(
    **project_data
)

# 现在的代码
project_data = {
  "detail": {
      "url": "xxx"
      "article": {
          "title": "项目标题",
      }
  }
}
project = Project(
    url=project_data["detail"]["url"],
    title=project_data["detail"]["article"]["title"],
)

from jmespath import search
project_data = {
    "detail": {
        "article": {
            "title": "项目标题",
        }
    }
}

title = search("detail.article.title", project_data)
assert title == "项目标题"  # True

# 即使是path不存在，也不会异常，而是返回None
assert search("detail.article.title1", project_data) is None  # True

class Project(BaseModel):
    url: str = Field(...)
    title: str = Field(...)
    content: str = Field(...)
    company: List[Dict] = Field(default=[])
    industry: str = Field(...)

    @root_validator(pre=True, skip_on_failure=True)
    def data_converter(cls, v):
        return {
            "url": search("detail.id", v),
            "title": search("detail.article.title", v),
            "content": search("detail.article.content", v),
            "company": search("company[*].name", v),
            "industry": search("industry", v)
        }
    
    @validator("url")
    def url_validator(cls, v):
        # 由于这里的v是拿到的ID，需要组合成url
        return f"https://xxxxx/{v}"

class Project(BaseModel):
    url: str = Field(..., path="temporaryLibrary.id")
    company_names: str = Field(..., path="company[0].enterprise.name")
    versions: List[str] = Field(..., path="versionList[*].id")

class ProjectGetter(GetterDict):

    def get(self, key: str, default: Any) -> Any:  # noqa
        # 由于getter_dict所能拿到的“数据权限”相对较低，
        # 也就是它的权限仅仅是处理数据，而不是处理模型，
        # 所以我们需要自己去拿到模型，然后再去拿到path
        model, data = self._obj['model'], self._obj['data']
        for name, field in model.__fields__.items():
            path = field.field_info.extra.get('path')
            if path and name == key:
                return search(path, data)
        return default


class Project(BaseModel):
    url: str = Field(..., path="detail.id")
    company_names: str = Field(..., path="company[0].enterprise.name")
    versions: List[str] = Field(..., path="versionList[*].id")

    @validator("url")
    def url_validator(cls, v):
        return f"https://www.baidu.com/{v}"

    class Config:
        # 通过orm_mode指定数据的来源
        orm_mode = True
        # 通过getter_dict指定数据的获取方式
        getter_dict = ProjectGetter

project_data = {
    "detail": {
        "id": 1,
        "article": {
            "title": "项目标题",
        }
    },
    "company": [
      {
        "enterprise": {
          "name": "企业名称1"
        }
      },
      {
        "enterprise": {
          "name": "企业名称2"
        }
      }
    ],
    "versionList": [{"id": "1.0"}, {"id": "2.0"}]
}
project = Project.from_orm({"model": Project, "data": project_data})
print(project)
# url='https://www.baidu.com/1' company_names='企业名称1' versions=['1.0', '2.0']