如何在 azure 函数中读取文件（在发布请求中）？

Posted 2023-04-13

【中文标题】如何在 azure 函数中读取文件（在发布请求中）？

【英文标题】：How to read a file (in a post request) in azure functions?

【发布时间】：2021-11-16 01:33:09

【问题描述】：

我通过 Post 请求发布了一个 txt 文件，我想读取它并将其存储在一个字符串中，以便我可以在该字符串上使用认知服务。我尝试将动态数据变量转换为字符串，但是当我记录它时，它是空白的，streamreader 也是如此。流式阅读器不应该有一些文字吗？

下面是我的代码。

using System;
using System.IO;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Azure.WebJobs;
using Microsoft.Azure.WebJobs.Extensions.Http;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Logging;
using Newtonsoft.Json;
using Microsoft.WindowsAzure.Storage.Blob;
using Microsoft.WindowsAzure.Storage;
using Microsoft.Azure.ServiceBus;
using System.Text;

namespace Demo1

    public static class Function1
    
        [FunctionName("Function1")]
        public static async Task<IActionResult> Run(
            [HttpTrigger(AuthorizationLevel.Function, "get", "post", Route = null)] HttpRequest req,
            ILogger log)
        
            log.LogInformation("C# HTTP trigger function processed a request.");

            Person p = new Person();

            string fname = req.Query["fname"];
            string lname = req.Query["lname"];
            

            string requestBody = await new StreamReader(req.Body).ReadToEndAsync();
            log.LogInformation("data to store is" + requestBody);
            dynamic data = JsonConvert.DeserializeObject(requestBody);
            //fname = fname ?? data?.fname;
            //lname = lname ?? data?.lname;
           string text = Convert.ToString(data);
            log.LogInformation("data to store is"+text);

            if (!string.IsNullOrEmpty(fname))
            
                p.firstName = fname;
                p.lasttName = lname;
                p.text = text;

                //string filename = fname+".txt";
                Guid g = Guid.NewGuid();
                string filename = g + ".txt";
                await CreateBlob(filename, p, log, filename);

            

            string responseMessage = string.IsNullOrEmpty(fname)
                ? "This HTTP triggered function executed successfully. Pass a name in the query string or in the request body for a personalized response."
                : $"Hello, fname lname.";

            return new OkObjectResult(responseMessage);
         

【问题讨论】：

查看您的代码，您的函数似乎需要一个 JSON 主体。那是您在 POST API 调用中传递的内容吗？您能否使用 POST API 调用的截图来编辑问题（可能通过邮递员）。还有 CreateBlob 函数在哪里？

【参考方案1】：

要在发布请求中读取文件，您可以使用Http Request Form 获取文件详细信息。

使用InputStream 读取文件。检查以下代码以供参考。

using System;
using System.IO;
using System.Web;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Azure.WebJobs;
using Microsoft.Azure.WebJobs.Extensions.Http;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Logging;
using Newtonsoft.Json;
namespace functionreadfile

    public  static  class  Function1
    
        [FunctionName("Function1")]
        public  static  async Task<IActionResult> Run(
[HttpTrigger(AuthorizationLevel.Anonymous, "get", "post", Route = null)] HttpRequest req,
ILogger log)
        
            log.LogInformation("C# HTTP trigger function processed a request.");
            var formdata = await req.ReadFormAsync();
            var filePath = "D:\\";
            string name = formdata["name"];
            var textfile = req.Form.Files["file"];
            if (textfile.Length > 0)
            
                using (var inputStream = new FileStream(filePath + textfile.FileName, FileMode.Create))
                
                    // read file to stream
                        await textfile.CopyToAsync(inputStream);
                    // stream to byte array
                    byte[] array = new  byte[inputStream.Length];
                    inputStream.Seek(0, SeekOrigin.Begin);
                    inputStream.Read(array, 0, array.Length);
                    // get file name
                    string fName = textfile.FileName;
                
            
            string requestBody = await  new StreamReader(req.Body).ReadToEndAsync();
            dynamic data = JsonConvert.DeserializeObject(requestBody);
            name = name ?? data?.name;
            string responseMessage = string.IsNullOrEmpty(name)
            ? "This HTTP triggered function executed successfully. Pass a name in the query string or in the request body for a personalized response."
            : $"Hello, name. This HTTP triggered function executed successfully.";
            return  new OkObjectResult(responseMessage);
        
    

您可以在代码中使用它来读取文件。