WebScraping in asp.net core 3.1 [Answered] RSS

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  eduardofnawu...

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  WebScraping in asp.net core 3.1

  Mar 15, 2021 12:26 PM|eduardofnawusjdnfa|LINK

  Hello guys. I'm trying to make a web scraper, but this error appears in GetAsync (). Does anyone know for what reason?

  Thanks

  The code:

  using Microsoft.AspNetCore.Mvc;
  using Microsoft.AspNetCore.Http;
  using System;
  using System.Collections.Generic;
  using System.Linq;
  using System.Threading.Tasks;
  using Microsoft.Extensions.Logging;
  using AngleSharp;
  using AngleSharp.Html.Parser;
  
  namespace web_scraper.Controllers
  {
      [Route("[controller]")]
      [ApiController]
      public class WebScraperController : ControllerBase
      {
          private readonly ILogger<WebScraperController> _logger;
  
          public WebScraperController(ILogger<WebScraperController> logger)
          {
              _logger = logger;
          }
  
          [HttpGet]
          public async Task<string> GetAsync() //O erro aparece aqui em GetAsync()
          {
              var config = Configuration.Default.WithDefaultLoader();
              var context = BrowsingContext.New(config);
              var document = await context.OpenAsync("https://www.americanas.com.br/produto/1951947793?opn=YSMESP&sellerid=23060006000150&epar=bp_pl_00_go_tel_smartphone_todas_geral_gmv&WT.srch=1&acc=e789ea56094489dffd798f86ff51c7a9&i=5d32878c49f937f6252da60d&o=5f3bf3b0f8e95eac3dd8a860&gclid=CjwKCAiAhbeCBhBcEiwAkv2cYx7Q2RhUaBWOLTd3CimKTQeF7d3uum9gohFS2DeUICC_7lvivUHmyBoCOn4QAvD_BwE");
              _logger.LogInformation(document.DocumentElement.OuterHtml);
          }
      }
  }

  The error mensage:

  "WebScraperController.GetAsync()": nem todos os caminhos de código retornam um valor

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  mgebhard

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  Re: WebScraping in asp.net core 3.1

  Mar 15, 2021 12:31 PM|mgebhard|LINK

  The error, "Not all code paths return a value",  is very clear.  You've defined the action method to return a string but the method body does not return a string. 

  C# Programming Guide.

  https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/classes-and-structs/methods

• • Reply
  eduardofnawu...

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  Re: WebScraping in asp.net core 3.1

  Mar 15, 2021 02:18 PM|eduardofnawusjdnfa|LINK

  thanks, with your comment i managed to understand the code better and fixed the error.

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  eduardofnawu...

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  Re: WebScraping in asp.net core 3.1

  Mar 15, 2021 02:20 PM|eduardofnawusjdnfa|LINK

  The right code:

          [HttpGet]
          public async Task GetAsync()
          //public async Task<float> GetAsync()
          {
              var config = Configuration.Default.WithDefaultLoader();
              var context = BrowsingContext.New(config);
              var document = await context.OpenAsync("https://deals.dell.com/pt-br/productdetail/6fmh");
              _logger.LogInformation(document.DocumentElement.OuterHtml);
          }