使用wklej API生成短链接时POST请求报错求助

我尝试通过wklej.to的API缩短链接，但该网站仅提供PHP版文档，无法自行排查问题。官方给出的示例请求如下：

https://wklej.to/api/url/add

$curl = curl_init();

curl_setopt_array($curl, array(
    CURLOPT_URL => "https://wklej.to/api/url/add",
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_ENCODING => "",
    CURLOPT_MAXREDIRS => 2,
    CURLOPT_TIMEOUT => 10,
    CURLOPT_FOLLOWLOCATION => true,
    CURLOPT_CUSTOMREQUEST => "POST",
    CURLOPT_HTTPHEADER => array(
        "Authorization: Bearer HERE IS MY API KEY",
        "Content-Type: application/json",
    ),
    CURLOPT_POSTFIELDS => '{
    "url": "https:\/\/google.com",
    "custom": "google",
    "password": "mypass",
    "expiry": "2020-11-11 12:00:00",
    "type": "splash",
    "metatitle": "Not Google",
    "metadescription": "Not Google description",
    "metaimage": "https:\/\/www.mozilla.org\/media\/protocol\/img\/logos\/firefox\/browser\/og.4ad05d4125a5.png",
    "geotarget": [
        {
            "location": "Canada",
            "link": "https:\/\/google.ca"
        },
        {
            "location": "United States",
            "link": "https:\/\/google.us"
        }
    ],
    "devicetarget": [
        {
            "device": "iPhone",
            "link": "https:\/\/google.com"
        },
        {
            "device": "Android",
            "link": "https:\/\/google.com"
        }
    ],
    "languagetarget": [
        {
            "language": "en",
            "link": "https:\/\/google.com"
        },
        {
            "language": "fr",
            "link": "https:\/\/google.ca"
        }
    ],
    "parameters": [
        {
            "name": "aff",
            "value": "3"
        },
        {
            "device": "gtm_source",
            "link": "api"
        }
    ]
}',
));

$response = curl_exec($curl);

curl_close($curl);
echo $response;

第一次尝试的错误 #

我最初用Python发送了如下请求：

r = requests.post("https://wklej.to/api/url/add", data = {"api": "HERE IS MY API KEY", "url": "https://amazon.com"})

收到的响应是：

{"error":1,"message":"A valid API key is required to use this service."}

我刚学Python，推测需要发送JSON格式的请求，而且API文档说明只需指定待缩短链接和API密钥，其余为可选参数。

更新后的问题 #

调整请求后代码如下：

headers = {
    'Authorization': 'Bearer MY_API_KEY',
    'Content-Type': 'application/json',
}

data = {"url": "https://amazon.com"}

r = requests.post("https://wklej.to/api/url/add", headers=headers, data=data)

但响应还是报错：

{"error":1,"message":"Missing required parameter: url"}

明明已经在data里设置了url，为什么还提示缺少这个参数？

解决方案 #

问题出在requests.post的参数使用上：

• 当你用data参数传入字典时，requests默认会把数据编码成application/x-www-form-urlencoded格式（表单格式），但API期望的是application/json格式的请求体。
• 正确的做法是使用json参数代替data，requests会自动把字典序列化成JSON字符串，并设置正确的Content-Type（你手动设置的header也可以保留）。

修正后的代码：

headers = {
    'Authorization': 'Bearer MY_API_KEY',
}

data = {"url": "https://amazon.com"}

r = requests.post("https://wklej.to/api/url/add", headers=headers, json=data)

如果你坚持用data参数，需要手动把字典转成JSON字符串：

import json

headers = {
    'Authorization': 'Bearer MY_API_KEY',
    'Content-Type': 'application/json',
}

data = json.dumps({"url": "https://amazon.com"})

r = requests.post("https://wklej.to/api/url/add", headers=headers, data=data)

这样API就能正确识别到url参数了。

内容的提问来源于stack exchange，提问作者Koke