facing issues in executing Azure vision api - azure

Question

Hello All I am using Azure's vision analyze api to extract text from my documents,
here is the example code for your reference
//My main function fi.fullfile is the path of my uploaded document
AzureAnalyzeRequest(System.IO.File.ReadAllBytes(fi.FullName));
analyze function
static async void AzureAnalyzeRequest(byte[] byteData)
{
var client = new HttpClient();
var queryString = HttpUtility.ParseQueryString(string.Empty);
// Request headers
client.DefaultRequestHeaders.Add("Ocp-Apim-Subscription-Key", "MyKey");
// Request parameters
queryString["language"] = "en";
queryString["pages"] = "1,2";
var uri = "https://url-ocr.cognitiveservices.azure.com/vision/v3.2/read/analyze?" + queryString;
HttpResponseMessage response;
using (var content = new ByteArrayContent(byteData))
{
content.Headers.ContentType = new MediaTypeHeaderValue("application/json");
response = await client.PostAsync(uri, content);
}
}
when the above function executed I am getting the error of 400 bad request
but when I tested my api on the below URL
Azure Vision api
it worked fine.
what I am doing wrong here?

Answer 1

According to this MSDOCS the api needs a Json object in the following form:
{
"url":""
}
I think you are passing a byte array, you need a Json object which will contain a URL of the image you want to process.
So here I have created a class called Poco which will host the URL variable.
public class Poco
{
public string url { get; set; }
}
Then I initialized the class and passed the URL then convert that object into a Json object.
Poco p = new Poco();
p.url = "<URL OF YOUR IMAGE>";
string json = JsonConvert.SerializeObject(p);
// Here we are converting the json string to stringcontent which we can pass to httpclient
StringContent data = new StringContent(json, Encoding.UTF8, "application/json");
Now all you have to do is call the Api:
HttpClient client = new HttpClient();
client.DefaultRequestHeaders.Add("Ocp-Apim-Subscription-Key", "<YOURKEY>");
var response = client.PostAsync(url, data);
Console.WriteLine(response.Result.StatusCode);
Console.WriteLine(response.Result);
If you want to use the byte array of image, then I think the content-type header should be application/octet-stream according to this MSDOC