c# - 将数组发布到 Azure Function HTTP 触发器返回 500 状态代码

Question

我有一个非常简单的 Azure HTTP 触发函数，它接收带有数据的 POST:

{
    "symbols": ["Azure1", "Azure2", "Azure3"]
}

我的 Azure 函数是:

#r "Newtonsoft.Json"
using System.Net;
using System.Linq;
using System.Net.Http;
using System.Net.Http.Formatting;
using System.Net.Http.Headers;
using Newtonsoft.Json;
using Newtonsoft.Json.Linq;

public static async Task<HttpResponseMessage> Run(HttpRequestMessage req, TraceWriter log)
{
    log.Info("C# HTTP trigger function processed a request.");

    // parse query parameter
    string symbols = req.GetQueryNameValuePairs()
        .FirstOrDefault(q => string.Compare(q.Key, "symbol", true) == 0)
        .Value;

    // Get request body
    dynamic data = await req.Content.ReadAsAsync<object>();

    // Set name to query string or body data
    symbols = symbols ?? data?.symbols;

    return symbols == null
        ? req.CreateResponse(HttpStatusCode.BadRequest, "Please pass a name on the query string or in the request body")
        : req.CreateResponse(HttpStatusCode.OK, symbols, JsonMediaTypeFormatter.DefaultMediaType);
}

但是，我收到带有错误消息的 500 响应:无法将类型“Newtonsoft.Json.Linq.JArray”隐式转换为“字符串”。存在显式转换(是否缺少强制转换？)。

有没有人看到我可能哪里出错了？我的期望是函数响应是:

["Azure1", "Azure2", "Azure3"]

Answer 1

这个错误是有道理的。您将 symbols 声明为 string，但稍后将 data?.symbols 分配给它，这是一个数组。因此消息 Cannot implicitly convert type 'Newtonsoft.Json.Linq.JArray' to 'string'。

除非您想支持通过查询字符串传递数据，否则您应该摆脱该查询字符串逻辑。例如试试这个:

#r "Newtonsoft.Json"
using System.Net;
using System.Net.Http;
using System.Net.Http.Formatting;
using Newtonsoft.Json.Linq;

public static async Task<HttpResponseMessage> Run(HttpRequestMessage req, TraceWriter log)
{
    dynamic data = await req.Content.ReadAsAsync<object>();
    JArray symbols = data?.symbols;

    return symbols == null
        ? req.CreateResponse(HttpStatusCode.BadRequest, "Please pass symbols in the body")
        : req.CreateResponse(HttpStatusCode.OK, symbols, JsonMediaTypeFormatter.DefaultMediaType);
}