尝试在天蓝色函数中使用绑定名称作为参数时出现 System.InvalidOperationException答案

【问题标题】：System.InvalidOperationException when trying use binding name as parameter in an azure function尝试在天蓝色函数中使用绑定名称作为参数时出现 System.InvalidOperationException
【发布时间】：2019-01-02 05:49:46
【问题描述】：

按照本教程chain-azure-functions-data-using-bindings，使用 JavaScript 时它可以工作，但是使用 .net 作为运行时堆栈创建了一个新的函数应用程序，添加了所需的 cosmos db 映射，当发送带有查询参数的 GET 请求时 https://azurefuncurl?code=abc&id=docs appinsights 显示由于 System.InvalidOperationException 导致 azure 函数/主机无法启动

尝试通过官方文档：azure-functions/configInput-Usage，没有运气

函数.json

{
 "bindings": [
{
  "authLevel": "function",
  "name": "req",
  "type": "httpTrigger",
  "direction": "in",
  "methods": [
    "get",
    "post"
  ]
},
{
  "name": "$return",
  "type": "http",
  "direction": "out"
},
{
  "type": "cosmosDB",
  "name": "bookmark",
  "databaseName": "func-io-learn-db",
  "collectionName": "Bookmarks",
  "connectionStringSetting": "chainazurefunctions_DOCUMENTDB",
  "id": "{id}",
  "partitionKey": "{id}",
  "direction": "in"
 }]
}

运行.csx

#r "Newtonsoft.Json"
using System.Net;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Primitives;
using Newtonsoft.Json;

public static async Task<IActionResult> Run(HttpRequest req, ILogger log, dynamic bookmark)
{

log.LogInformation("C# HTTP trigger function processed a request.");

string name = req.Query["id"];

string requestBody = await new StreamReader(req.Body).ReadToEndAsync();
dynamic data = JsonConvert.DeserializeObject(requestBody);
name = name ?? data?.name;

return name != null
    ? (ActionResult)new OkObjectResult($"Hello, {name}")
    : new BadRequestObjectResult("Please pass a name on the query string or in the request body");
}

异常信息：

Error indexing method 'Functions.find-bookmark' Unable to resolve binding parameter 'id'. Binding expressions must map to either a value provided by the trigger or a property of the value the trigger is bound to, or must be a system binding expression (e.g. sys.randguid, sys.utcnow, etc.).

【问题讨论】：

标签： azure azure-functions csx

【解决方案1】：

只需将{id} 替换为{Query.id}，看看csx sample。

【讨论】：

谢谢，我看的不够仔细

【解决方案2】：

供日后参考 基于Jerry Liu's recommendation , 我必须在 function.json 中用 {Query.id} 替换 id，就像键 id 和 partitionKey 中的注释值一样

{
  "type": "cosmosDB",
  "name": "bookmark",
  "databaseName": "func-io-learn-db",
  "collectionName": "Bookmarks",
  "connectionStringSetting": "chainazurefunctions_DOCUMENTDB",
  "id": "{Query.id}",
  "partitionKey": "{Query.id}",
  "direction": "in"
}

在 run.csx 中

创建一个 POCO 模型类并将其用作 Run 方法中的参数，下面是整个 run.csx 的样子

#r "Newtonsoft.Json"

using System.Net;
using Microsoft.Extensions.Primitives;
using Newtonsoft.Json;
using System.Text;

public class Bookmark
{
    [JsonIgnore]
    public string id {get; set;}

    [JsonProperty(PropertyName ="url")]
    public string URL {get;set;}

}

public static HttpResponseMessage  Run(HttpRequest  req, ILogger log, Bookmark bookmark)
{
    log.LogInformation("C# HTTP trigger function processed a request.");

    if(bookmark == null)
    {        
        string id = req.Query["id"];
        log.LogInformation($"Bookmark item {id} not found");

        return new HttpResponseMessage(HttpStatusCode.NotFound)
        {
            Content = new StringContent($"{id} not found", Encoding.UTF8, "application/json")
        };
    }
    else
    {
        log.LogInformation($"Found item {bookmark.URL}");
        return new HttpResponseMessage(HttpStatusCode.OK)
        {
            Content = new StringContent(JsonConvert.SerializeObject(bookmark), Encoding.UTF8, "application/json")
        };
    }
}

【讨论】：