C#•9mo ago

How do I do a HTTP request in C#?

 public static async Task<string> MessageAI(string user, string system)
 {
     HttpClient client = new();
     client.BaseAddress = new("http://localhost:1234");
     client.DefaultRequestHeaders
         .Accept
         .Add(new MediaTypeWithQualityHeaderValue("application/json")); 
     var json = @"{
         ""messages"": [
             {
                 ""role"": ""user"",
                 ""content"": user
             },
             {
                 ""role"": ""system"",
                 ""content"": system
             }
         ],
         ""temperature"": 0.7,
         ""max_tokens"": 80,
         ""stream"": false
     }";

     var content = new StringContent(json, System.Text.Encoding.UTF8, "application/json");
     
     var response = await client.PostAsync("http://localhost:1234/v1/chat/completions", content);
     var responseContent = await response.Content.ReadAsStringAsync();

     return responseContent;
 }

 public static async Task<string> MessageAI(string user, string system)
 {
     HttpClient client = new();
     client.BaseAddress = new("http://localhost:1234");
     client.DefaultRequestHeaders
         .Accept
         .Add(new MediaTypeWithQualityHeaderValue("application/json")); 
     var json = @"{
         ""messages"": [
             {
                 ""role"": ""user"",
                 ""content"": user
             },
             {
                 ""role"": ""system"",
                 ""content"": system
             }
         ],
         ""temperature"": 0.7,
         ""max_tokens"": 80,
         ""stream"": false
     }";

     var content = new StringContent(json, System.Text.Encoding.UTF8, "application/json");
     
     var response = await client.PostAsync("http://localhost:1234/v1/chat/completions", content);
     var responseContent = await response.Content.ReadAsStringAsync();

     return responseContent;
 }

I get bad request?

65 Replies

Saber•9mo ago

probably because your passing invalid json

RemOP•9mo ago

Hmm...

mtreit•9mo ago

Get it working via something like PostMan first

Saber•9mo ago

put a breakpoint and validate json contains what you think it should

RemOP•9mo ago

What's postman?

Pobiega•9mo ago

""content"": system

guaranteed to be broken

RemOP•9mo ago

I see

mtreit•9mo ago

It's a tool for making web requests

Pobiega•9mo ago

you are not actually adding the user/system to the body you are hardcoding in the word user and system without quotes

RemOP•9mo ago

felt like it How do I put variables into json?

Pobiega•9mo ago

interpolated string

RemOP•9mo ago

I know it works on the server side

mtreit•9mo ago

One way is to create a C# object that you then serialize to the JSON rather than hand-building the string

Pobiega•9mo ago

var user = "steve";
var system = "windows";

var json =
    $$"""
      {
       "messages": [
           {
               "role": "user",
               "content": "{{user}}",
           },
           {
               "role": "system",
               "content": "{{system}}"
           }
       ],
       "temperature": 0.7,
       "max_tokens": 80,
       "stream": false
      }
      """;

var user = "steve";
var system = "windows";

var json =
    $$"""
      {
       "messages": [
           {
               "role": "user",
               "content": "{{user}}",
           },
           {
               "role": "system",
               "content": "{{system}}"
           }
       ],
       "temperature": 0.7,
       "max_tokens": 80,
       "stream": false
      }
      """;

RemOP•9mo ago

Seems easier than what I just did lol

Pobiega•9mo ago

I still usually prefer mtreits suggestion of setting up actual types that reflect your structure and letting the system handle the json encoding

RemOP•9mo ago

hmm

Pobiega•9mo ago

but this is fine, if verbose

RemOP•9mo ago

thanks! Hmm.. It still seem to not work... I can do it via curl

curl http://localhost:1234/v1/chat/completions \
-H "Content-Type: application/json" \
-d '{ 
  "messages": [ 
    { "role": "system", "content": "Always answer in rhymes." },
    { "role": "user", "content": "Introduce yourself." }
  ], 
  "temperature": 0.7, 
  "max_tokens": -1,
  "stream": false
}'

curl http://localhost:1234/v1/chat/completions \
-H "Content-Type: application/json" \
-d '{ 
  "messages": [ 
    { "role": "system", "content": "Always answer in rhymes." },
    { "role": "user", "content": "Introduce yourself." }
  ], 
  "temperature": 0.7, 
  "max_tokens": -1,
  "stream": false
}'

but not in c#?

Pobiega•9mo ago

woops, no quotes around the values

RemOP•9mo ago

hmm

Pobiega•9mo ago

updated

RemOP•9mo ago

I see well I actually didn't use the values but I still can't get it to work properly?

Pobiega•9mo ago

set a breakpoint, verify that the body looks okay

RemOP•9mo ago

I'm not sure what a breakpoint is

Pobiega•9mo ago

$debug

MODiX•9mo ago

https://docs.microsoft.com/en-us/visualstudio/get-started/csharp/tutorial-debugger?view=vs-2022

Tutorial: Debug C# code and inspect data - Visual Studio (Windows)

Learn features of the Visual Studio debugger and how to start the debugger, step through code, and inspect data in a C# application.

Pobiega•9mo ago

time to learn 🙂

RemOP•9mo ago

breakpoint at the variable?

Pobiega•9mo ago

after the json variable is set, ye

mtreit•9mo ago

This is why I suggest using Postman. That verifies you are actually building a request the server accepts. Then you can compare what Postman sends over the wire with what your C# code does

RemOP•9mo ago

It says that json is null? should there be two dollar signs? okay I think I let it execute smart..

"{\r\n\"messages\": [\r\n    {\r\n        \"role\": \"user\",\r\n        \"content\": NPC name: Old Man,\r\n    },\r\n    {\r\n        \"role\": \"system\",\r\n        \"content\": Generate a description for this NPC.\r\n    }\r\n   ],\r\n\"temperature\": 0.7,\r\n\"max_tokens\": 80,\r\n\"stream\": false\r\n}"

"{\r\n\"messages\": [\r\n    {\r\n        \"role\": \"user\",\r\n        \"content\": NPC name: Old Man,\r\n    },\r\n    {\r\n        \"role\": \"system\",\r\n        \"content\": Generate a description for this NPC.\r\n    }\r\n   ],\r\n\"temperature\": 0.7,\r\n\"max_tokens\": 80,\r\n\"stream\": false\r\n}"

this is the value of json should there be \r?

Pobiega•9mo ago

\r is carriage return \r\n is a windows style newline

RemOP•9mo ago

I see What should I look out for?

leowest•9mo ago

or just do proper classes to serialize instead of fighting text to fit

Pobiega•9mo ago

if the start and end quotes are there, thats probably why also uh this is super invalid

RemOP•9mo ago

I see

Pobiega•9mo ago

"{
"messages": [
    {
        "role": "user",
        "content": NPC name: Old Man,
    },
    {
        "role": "system",
        "content": Generate a description for this NPC.
    }
   ],
"temperature": 0.7,
"max_tokens": 80,
"stream": false
}"

"{
"messages": [
    {
        "role": "user",
        "content": NPC name: Old Man,
    },
    {
        "role": "system",
        "content": Generate a description for this NPC.
    }
   ],
"temperature": 0.7,
"max_tokens": 80,
"stream": false
}"

thats what you are sending

RemOP•9mo ago

hmm probably incorrect yes

Pobiega•9mo ago

wdym probably lol

RemOP•9mo ago

nothing lol

Pobiega•9mo ago

json validity is a boolean state 😄

RemOP•9mo ago

I didn't know you could turn classes into json?

Pobiega•9mo ago

thats how you normally do it

RemOP•9mo ago

😔 guess they need to invent those quantum computers soon so I can have a probably valid json hmm

leowest•9mo ago

var chat = new Chat
{
    Messages =
    [
        new Message
        {
            Role = "user",
            Content = user
        },
        new Message
        {
            Role = "system",
            Content = system
        },
    ],
    Temperature = 0.7,
    MaxTokens = 80,
    stream = false
};

public class Chat
{
    [JsonPropertyName("messages")]
    public List<Message> Messages { get; set; }

    [JsonPropertyName("temperature")]
    public double Temperature { get; set; }

    [JsonPropertyName("max_tokens")]
    public long MaxTokens { get; set; }

    [JsonPropertyName("stream")]
    public bool Stream { get; set; }
}

public class Message
{
    [JsonPropertyName("role")]
    public string Role { get; set; }

    [JsonPropertyName("content")]
    public string Content { get; set; }
}

var chat = new Chat
{
    Messages =
    [
        new Message
        {
            Role = "user",
            Content = user
        },
        new Message
        {
            Role = "system",
            Content = system
        },
    ],
    Temperature = 0.7,
    MaxTokens = 80,
    stream = false
};

public class Chat
{
    [JsonPropertyName("messages")]
    public List<Message> Messages { get; set; }

    [JsonPropertyName("temperature")]
    public double Temperature { get; set; }

    [JsonPropertyName("max_tokens")]
    public long MaxTokens { get; set; }

    [JsonPropertyName("stream")]
    public bool Stream { get; set; }
}

public class Message
{
    [JsonPropertyName("role")]
    public string Role { get; set; }

    [JsonPropertyName("content")]
    public string Content { get; set; }
}

then just serialize chat instead 🙂

RemOP•9mo ago

uhuh...

leowest•9mo ago

so it would literally just be

var json = JsonSerializer.Serialize(chat);

var json = JsonSerializer.Serialize(chat);

Pobiega•9mo ago

or use JsonContent

leowest•9mo ago

with System.Text.Json

Pobiega•9mo ago

or PostAsJsonAsync

leowest•9mo ago

yep that works too and sorry to interrupt mid journey 🙂

RemOP•9mo ago

😂 it's no mid journey

Pobiega•9mo ago

record RootObject(
    List<Message> Messages,
    double Temperature,
    [property: JsonPropertyName("max_tokens")]
    int MaxTokens,
    bool Stream);

record Message(string Role, string Content);

public static async Task<string> MessageAI(string user, string system)
{
    var obj = new RootObject([new Message("user", user), new Message("system", system)], 0.7d, 80, false);

    HttpClient client = new();
    client.BaseAddress = new("http://localhost:1234");
    client.DefaultRequestHeaders
        .Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));

    var response = await client.PostAsJsonAsync("http://localhost:1234/v1/chat/completions", obj);
    var responseContent = await response.Content.ReadAsStringAsync();

    return responseContent;
}

record RootObject(
    List<Message> Messages,
    double Temperature,
    [property: JsonPropertyName("max_tokens")]
    int MaxTokens,
    bool Stream);

record Message(string Role, string Content);

public static async Task<string> MessageAI(string user, string system)
{
    var obj = new RootObject([new Message("user", user), new Message("system", system)], 0.7d, 80, false);

    HttpClient client = new();
    client.BaseAddress = new("http://localhost:1234");
    client.DefaultRequestHeaders
        .Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));

    var response = await client.PostAsJsonAsync("http://localhost:1234/v1/chat/completions", obj);
    var responseContent = await response.Content.ReadAsStringAsync();

    return responseContent;
}

RemOP•9mo ago

looks more complicated

Pobiega•9mo ago

but it works

RemOP•9mo ago

looks good then

Pobiega•9mo ago

unlike your 10+ attempts at doing it yourself 🙂 manually writing json is a mess

leowest•9mo ago

he just made a onliner out of my classes into a record

Pobiega•9mo ago

avoid when possible

leowest•9mo ago

in terms of how different it is but yes create DTOs to represent your json it will save your life

Pobiega•9mo ago

this is the "shortest" way to do it properly, but it also means you will get chunked transfer encoding if the webserver doesnt support that, there are workarounds. as I found out the hard way at work a few days ago 😄

RemOP•9mo ago

well I want to use leowest's example but the class is not a string nor httpcontent? wait- I forgot the other part

leowest•9mo ago

you have to create the objets then serialize it or use the method pobi said above PostAsJsonAsync with what u have it would be something like this

var json = JsonSerializer.Serialize(chat);
var content = new StringContent(json, System.Text.Encoding.UTF8, "application/json");

var json = JsonSerializer.Serialize(chat);
var content = new StringContent(json, System.Text.Encoding.UTF8, "application/json");

with what pobi suggested it would be just

var response = await client.PostAsJsonAsync("v1/chat/completions", chat);

var response = await client.PostAsJsonAsync("v1/chat/completions", chat);

you choose whichever u feel more confortable with

Pobiega•9mo ago

and you can mix and match you could use the classes, but still use PostAsJson I would normally add a helper method with records like thesee

record Message(string Role, string Content);

record RootObject(
    List<Message> Messages,
    double Temperature,
    [property: JsonPropertyName("max_tokens")]
    int MaxTokens,
    bool Stream)
{
    public static RootObject Create(string user, string system, double temperature, int maxTokens,
        bool stream = false) =>
        new([new Message("user", user), new Message("system", system)], temperature, maxTokens, stream);
}

public static async Task<string> MessageAI(string user, string system)
{
    var obj = RootObject.Create(user, system, 0.7d, 80);

    HttpClient client = new();
    client.BaseAddress = new("http://localhost:1234");
    client.DefaultRequestHeaders
        .Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));

    var response = await client.PostAsJsonAsync("http://localhost:1234/v1/chat/completions", obj);
    var responseContent = await response.Content.ReadAsStringAsync();

    return responseContent;
}

record Message(string Role, string Content);

record RootObject(
    List<Message> Messages,
    double Temperature,
    [property: JsonPropertyName("max_tokens")]
    int MaxTokens,
    bool Stream)
{
    public static RootObject Create(string user, string system, double temperature, int maxTokens,
        bool stream = false) =>
        new([new Message("user", user), new Message("system", system)], temperature, maxTokens, stream);
}

public static async Task<string> MessageAI(string user, string system)
{
    var obj = RootObject.Create(user, system, 0.7d, 80);

    HttpClient client = new();
    client.BaseAddress = new("http://localhost:1234");
    client.DefaultRequestHeaders
        .Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));

    var response = await client.PostAsJsonAsync("http://localhost:1234/v1/chat/completions", obj);
    var responseContent = await response.Content.ReadAsStringAsync();

    return responseContent;
}

the method itself becomes very clean and easy to use then the records you can "hide" in some other file somewhere 😄

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How do I do a HTTP request in C#?