wp_remote_post调用FastAPI接口报422错误的排查与解决

问题场景 #

本地服务器同时部署FastAPI接口与WordPress插件，接口通过Swagger UI、Python requests库调用均正常，但在WordPress插件中使用wp_remote_post调用时返回422错误。

FastAPI接口代码 #

from fastapi import FastAPI
from pydantic import BaseModel
from api.article import add_article, html_format_data

app = FastAPI()

class PostData(BaseModel):
    links: list
    title: str

@app.post('/create_post/')
def create_post(post_data: PostData):
    html_format = html_format_data(post_data.links, post_data.title)  # list of dicts
    if add_article(post_data.title, html_format):
        return {"status": 201, "success": True}
    else:
        return {"error"}

正常工作的Python请求代码 #

import requests

data = {
    "title": "gaming",
    "links": [
        {
            "id": "video id 1",
            "thumbnail": "url of thumbnail 1",
            "title": "title of video 1"
        },
        {
            "id": "video id 2",
            "thumbnail": "url of thumbnail 2",
            "title": "title of video 2"
        }
    ]
  }
res = requests.post('http://127.0.0.1:5000/create_post/', json=data)
print(res.content)

Swagger UI生成的curl调用示例 #

curl -X 'POST' \
  'http://127.0.0.1:5000/create_post/' \
  -H 'accept: application/json' \
  -H 'Content-Type: application/json' \
  -d '{
  "links": [
  {
    "id": "shortand",
    "thumbnail": "shortand",
    "title": "shortand"
  },
  {
    "id": "shortand",
    "thumbnail": "shortand",
    "title": "shortand"
  }
],
  "title": "gaming"
}'

WordPress插件中错误的调用代码 #

function create_post( $data, $query ) {
    $url = 'http://127.0.0.1:5000/create_post/';
    
    $arguments = array(
        'method' => 'POST',
        'body' => json_encode(array(
                "links" => $data,
                "title" => $query
                )),
        'header' => array(
            'Content-Type' => 'application/json',
            'accept' => 'application/json'
            )
        );
    
    $response = wp_remote_post( $url, $arguments );
//  echo '<script>console.log(`data: ' . $arguments["body"] . '`)</script>';
    echo '<script>console.log(`' . json_encode($response) . '`)</script>';
}

报错信息 #

{"headers":{},"body":"{\"detail\":[{\"loc\":[\"body\"],\"msg\":\"value is not a valid dict\",\"type\":\"type_error.dict\"}]}","response":{"code":422,"message":"Unprocessable Entity"},"cookies":[],"filename":null,"http_response":{"data":null,"headers":null,"status":null}}

解决过程与修正方案 #

排查后发现核心问题是wp_remote_post的参数拼写错误：将请求头参数的复数形式headers误写为单数header。这导致FastAPI无法识别请求的Content-Type，进而无法正确解析JSON格式的请求体，返回422验证错误。

修正后的WordPress调用代码：

function create_post( $data, $query ) {
    $url = 'http://127.0.0.1:5000/create_post/';
    
    $arguments = array(
        'method' => 'POST',
        'body' => json_encode(array(
                "links" => $data,
                "title" => $query
                )),
        'headers' => array( // 修正为复数形式headers
            'Content-Type' => 'application/json',
            'accept' => 'application/json'
            )
        );
    
    $response = wp_remote_post( $url, $arguments );
//  echo '<script>console.log(`data: ' . $arguments["body"] . '`)</script>';
    echo '<script>console.log(`' . json_encode($response) . '`)</script>';
}

内容的提问来源于stack exchange，提问作者SAVEPALASTINE