C# System.IndexOutOfRangeException: Index was outside the bounds of the array. But when I check it manualy it is within bounds of the array

Question

My problem is probably stupid, but I can't figure out the solution by myself, so I hope someone here can help me.

I am trying to make a dll file for hosting a server on the localhost. I thought I did everything right, but I receive this error:

System.IndexOutOfRangeException: Index was outside the bounds of the array.

at minihttpc.Requests.HttpRequest.ParseHeaders(String[] requestLine) in C:\Users\deqnb\OneDrive\minihttpc\minihttpc\Requests\HttpRequest.cs:line 87
at minihttpc.Requests.HttpRequest.ParseRequest(String requestString) in C:\Users\deqnb\OneDrive\minihttpc\minihttpc\Requests\HttpRequest.cs:line 44
at minihttpc.Requests.HttpRequest..ctor(String requestString) in C:\Users\deqnb\OneDrive\minihttpc\minihttpc\Requests\HttpRequest.cs:line 21
at MiniServerHTTP.WebServer.ConnectionHandler.ReadRequest() in C:\Users\deqnb\OneDrive\minihttpc\MiniServerHTTP.WebServer\ConnectionHandler.cs:line 80
at MiniServerHTTP.WebServer.ConnectionHandler.ProcessRequest() in C:\Users\deqnb\OneDrive\minihttpc\MiniServerHTTP.WebServer\ConnectionHandler.cs:line 28

Here is my code - HttpRequest.cs:

using minihttpc.Common.CoreValidator;
using minihttpc.Common.GlobalConstants;
using minihttpc.Headers;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace minihttpc.Requests
{
    public class HttpRequest:IHttpRequest
    {
        public HttpRequest(string requestString)
        {
            CoreValidator.ThrowIfNullOrEmpty(requestString, nameof(requestString));

            this.FormData = new Dictionary<string, object>();
            this.QueryData = new Dictionary<string, object>();
            this.Headers = new HttpHeaderCollection();

            this.ParseRequest(requestString);
        }

        public string Path { get; private set; }
        public string Url { get; private set; }
        public Dictionary<string,object>FormData { get; }
        public Dictionary<string, object> QueryData { get; }
        public IHttpHeaderCollection Headers { get; private set; }
        public HttpRequestMethod RequestMethod { get; private set; }

        public void ParseRequest(string requestString)
        {
            string[] splitRequestContent = requestString.Split(new[] { 
GlobalConstants.HttpNewLine }, StringSplitOptions.None);
            string[] requestLine = splitRequestContent[0].Trim().Split(new[] 
{ ' ' }, StringSplitOptions.RemoveEmptyEntries);

            if (!this.IsValidReqiestLine(requestLine))
            {
                throw new BadRequestException();
            }

            this.ParseRequestMethod(requestLine);
            this.ParseRequestUrl(requestLine);
            this.ParseRequestPath();
            this.ParseHeaders(splitRequestContent.Skip(1).ToArray());
            //this.ParseRequestQueryParameters();
            this.ParseRequestParameters(splitRequestContent[splitRequestContent.Length - 1]);
        }

        bool IsValidRequestLine(string[] requestLine)
        {
            if (requestLine.Count() != 3 && requestLine[2] != "HTTP/1.1")
            {
                return false;
            }
            else
            {
                return true;
            }
        }

        void ParseRequestMethod(string[] requestLine)
        {
            switch (requestLine[0])
            {
                case "GET": RequestMethod = HttpRequestMethod.Get; break;
                case "POST": RequestMethod = HttpRequestMethod.Post; break;
                case "PUT": RequestMethod = HttpRequestMethod.Put; break;
                case "DELETE": RequestMethod = HttpRequestMethod.Delete; break;
            }
        }

        void ParseRequestUrl(string [] requestLine)
        {
            this.Url = requestLine[1];
        }

        void ParseRequestPath()
        {
            this.Path = this.Url.Split("?").Take(1).First().ToString();
        }

        void ParseHeaders(string [] requestLine)
        {
            foreach(var line in requestLine)
            {
                Console.WriteLine(line); //a lot of info about the req
                if (line == GlobalConstants.HttpNewLine) break;

                string[] header = line.Split(' ').ToArray();
                //Console.WriteLine(header[1]);
                Headers.AddHeader(new HttpHeader(header[0],
 header[1]));//seems fine //line 87
            }

            if (Headers.ContainsHeader("host"))
            {
                throw new BadRequestException();
            }
        }

        void ParseRequestQueryParameters()
        {
            if (!(this.Url.Split('?').Length > 1)) return;
            this.Url.Split('?', '#')[1].Split('&').Select(plainQueryParameter => 
plainQueryParameter.Split());//not finished !!!!
        }

        void ParseFormDataParameters(string formData)
        {
            if (!string.IsNullOrEmpty(formData))
            {
                formData.Split('&').Select(plainQueryParameter => 
plainQueryParameter.Split('=')).ToList().ForEach(queryParameterKeyValue =>
                this.FormData.Add(queryParameterKeyValue[0], 
queryParameterKeyValue[1]));
            }
        }

        void ParseRequestParameters(string formData)//not being called
        {
            ParseRequestQueryParameters();
            ParseFormDataParameters(formData);
        }
    }
}

ConnectionHandler.cs:

using minihttpc.Common.CoreValidator;
using minihttpc.Requests;
using MiniServerHTTP.WebServer.Results;
using MiniServerHTTP.WebServer.Routing;
using System;
using System.Collections.Generic;
using System.Net.Sockets;
using System.Text;
using System.Threading.Tasks;

namespace MiniServerHTTP.WebServer
{
    public class ConnectionHandler
    {
        private readonly Socket client;
        private readonly IServerRoutingTable table;

        public ConnectionHandler(Socket client, IServerRoutingTable table)
        {
            CoreValidator.ThrowIfNull(client, nameof(client));
            CoreValidator.ThrowIfNull(client, nameof(client));
            this.client = client;
            this.table = table;
        }

        public async Task ProcessRequest()
        {
            try
            {
                var httpRequest = await this.ReadRequest();

                if (httpRequest != null)
                {
                    Console.WriteLine($"Processing: {httpRequest.RequestMethod} {httpRequest.Path}...");
                    var httpResponse = this.HandleRequest((IHttpRequest)httpRequest);
                    this.ProcessResponse(httpResponse);
                }
            }
            catch (BadRequestException e)//400
            {
                this.ProcessResponse(new TextResult(e.ToString(), 
HttpResponseStatusCode.BadRequest));
            }
            catch (Exception e)//500
            {
                this.ProcessResponse(new TextResult(e.ToString(), 
HttpResponseStatusCode.InternalServerError));
            }

            this.client.Shutdown(SocketShutdown.Both);
        }

        private async Task ProcessResponse(IHttpResponse httpResponse)
        {
            byte[] byteSegments = httpResponse.GetBytes();
            await this.client.SendAsync(byteSegments, SocketFlags.None);
        }

        private IHttpResponse HandleRequest(IHttpRequest httpRequest)
        {
            if(!this.table.Contains(httpRequest.RequestMethod, 
httpRequest.Path))
            {
                return new TextResult($"Route with method {httpRequest.RequestMethod} and path \"{httpRequest.Path}\"not found.", 
HttpResponseStatusCode.NotFound);
            }

            return this.table.Get(httpRequest.RequestMethod, 
httpRequest.Path).Invoke(httpRequest);
        }

        private async Task<HttpRequest> ReadRequest()
        {
            var result = new StringBuilder();
            var data = new ArraySegment<byte>(new byte[1024]);

            while (true)
            {
                int numberOfBytes = await this.client.ReceiveAsync(data.Array, SocketFlags.None);
                if (numberOfBytes == 0) break;
                var bytesAsString = Encoding.UTF8.GetString(data.Array, 0,
 numberOfBytes);
                result.Append(bytesAsString);

                if (numberOfBytes < 1023) break;
            }

            if (result.Length == 0)
            {
                return null;
            }

            return new HttpRequest(result.ToString());
        }
    }
}

When I check the parameters manually and variables in minihttpc.Requests.HttpRequest.ParseHeaders(), everything seems fine. I can't get where the problem is.

When you debug, which exact line of code produces the exception? What are the exact observed runtime values of the variables used in that line of code? "When I check [...] everything seems good" isn't really a specific debugging step or observation. — David, Nov 02 '22 at 16:10
If I count correctly, Line 87 is `new HttpHeader(header[0], header[1])`, right? So what is the value of `header` here? — Klaus Gütter, Nov 02 '22 at 16:31
Could you edit the code and add a comment at the line 87? Like this: `// line 87`. Also it would be nice if you could insert line-breaks in the long lines of code, so that all the code is visible doing only vertical scrolling. Horizontal scrolling is a pain. — Theodor Zoulias, Nov 02 '22 at 16:49
StriplingWarrior is correct. There was an empty line in the request. Anyway thank you all for the fast response. Theodor Zoulias, I will edit the question and will take a note for future questions. — Darg, Nov 02 '22 at 18:20
@marc_s personally I find exception-stack-traces formatted as code more readable than formatted as a quote! — Theodor Zoulias, Nov 11 '22 at 11:52

score 2 · Accepted Answer · answered Nov 02 '22 at 16:41

string[] header = line.Split(' ').ToArray();
Headers.AddHeader(new HttpHeader(header[0], header[1]));

I can pretty much guarantee you're running into a line that doesn't have a space in it. Maybe there's a line that's empty, for example. That wouldn't be obvious from the Console.WriteLine() that you're doing, because empty lines are kind of invisible.

C# System.IndexOutOfRangeException: Index was outside the bounds of the array. But when I check it manualy it is within bounds of the array

1 Answers1