How to retrieve response as URL from server to client

Question

I have PHP Server where i will send send request from client side and my request is going successfully but i want response from server which should be an URL and when i am trying to retrieve response(URL as response) from server then it is coming successfully but i am getting an Exception onto my StringContent Object. That is: =============================================================================

 {System.UriFormatException: Invalid URI: The format of the URI could not be determined.
  at System.Uri.CreateThis (System.String uri, System.Boolean dontEscape, System.UriKind uriKind) [0x0007b] in <ca7419b40e504a6dbe088f6fe95d09aa>:0 
  at System.Uri..ctor (System.String uriString, System.UriKind uriKind) [0x00014] in <ca7419b40e504a6dbe088f6fe95d09aa>:0 
  at MPTrain.view.ProductList.SendRequest () [0x001aa] in C:\nginx\www\repos\xformsexperimental\MPTrain\MPTrain\MPTrain\view\ProductList.xaml.cs:111 }

=============================================================================

I have tried in my server code:

   $sql =  "CALL FetchImage()";

    $res = mysqli_query($conn,$sql); 
    if($res == TRUE)
    {
        if (mysqli_num_rows($res) > 0) 
        {
            // output data of each row
            while($row = mysqli_fetch_assoc($res)) {
                echo json_encode($row);
            }
        }
    }

This is my client side code:

HttpClient client = new HttpClient();

client.BaseAddress = new Uri("http://192.168.1.011/repos/xformsexperimental/RestApiTrain/index.php");

Dictionary<object, object> keyValuePairs = new Dictionary<object, object>();
keyValuePairs.Add("eml", "Manisha");

var jsonData = JsonConvert.SerializeObject(keyValuePairs);
var content = new StringContent(jsonData, UnicodeEncoding.UTF8, "application/json");

var posttask = await client.PostAsync(client.BaseAddress.ToString(), content); //accessing response

var stringContent = await posttask.Content.ReadAsStringAsync();

// ResponseImage responseImage = JsonConvert.DeserializeObject<ResponseImage>(stringContent);

Uri uri = new Uri(stringContent,UriKind.Absolute);

My response which i am getting from server is:

=============================================================================

{\"image\":\"http:\\/\\/localhost\\/example\\/images\\/pic1.png\"}

=============================================================================

And i want an exact or absolute URL from server. How i can get it please help...

I tried This:

ResponseImage responseImage = JsonConvert.DeserializeObject<ResponseImage>(stringContent);

but i am getting this Exception onto stringContent

================================================================================ {Newtonsoft.Json.JsonReaderException: Additional text encountered after finished reading JSON content: {. Path '', line 3, position 0. at Newtonsoft.Json.JsonTextReader.Read () [0x000c7] in <12891e825fce44a581e5bbbb579c1d49>:0 at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.Deserialize (Newtonsoft.Json.JsonReader reader, System.Type objectType, System.Boolean checkAdditionalContent) [0x000db] in <12891e825fce44a581e5bbbb579c1d49>:0 at Newtonsoft.Json.JsonSerializer.DeserializeInternal (Newtonsoft.Json.JsonReader reader, System.Type objectType) [0x00054] in <12891e825fce44a581e5bbbb579c1d49>:0 at Newtonsoft.Json.JsonSerializer.Deserialize (Newtonsoft.Json.JsonReader reader, System.Type objectType) [0x00000] in <12891e825fce44a581e5bbbb579c1d49>:0 at Newtonsoft.Json.JsonConvert.DeserializeObject (System.String value, System.Type type, Newtonsoft.Json.JsonSerializerSettings settings) [0x0002d] in <12891e825fce44a581e5bbbb579c1d49>:0 at Newtonsoft.Json.JsonConvert.DeserializeObject[T] (System.String value, Newtonsoft.Json.JsonSerializerSettings settings) [0x00000] in <12891e825fc e44a581e5bbbb579c1d49>:0 at Newtonsoft.Json.JsonConvert.DeserializeObject[T] (System.String value) [0x00000] in <12891e825fce44a581e5bbbb579c1d49>:0

at MPTrain.view.ProductList.SendRequest () [0x001aa] in C:\\nginx\\www\\repos\\xformsexperimental\\MPTrain\\MPTrain\\MPTrain\\view\\ProductList.xaml.cs:112 }

Answer 1

The response appears to be JSON.

It appears you tried to have a strongly typed model so based on the shown JSON, the model should look like this

public class ResponseImage {
    public string image { get; set; }
}

in order to match the expected data

Parse the response and extract the desired information.

//...

ResponseImage responseImage = JsonConvert.DeserializeObject<ResponseImage>(stringContent);

Uri uri = new Uri(responseImage.image, UriKind.Absolute);

Now based on the server code

// output data of each row
while($row = mysqli_fetch_assoc($res)) {
    echo json_encode($row);
}

This has the potential to return malformed JSON if there are more than one row in the collection.

I would suggest you populate a proper collection and then return that as a JSON array.

//...

if (mysqli_num_rows($res) > 0)  {
    $result = array();
    // collect data of each row
    while($row = mysqli_fetch_assoc($res)) {
        $result[] = $row; //push data into array
    }
    echo json_encode($result);
}

//...

The client side code would then need to be updated to expected a collection instead of a single object.

ResponseImage[] responseImages = JsonConvert.DeserializeObject<ResponseImage[]>(stringContent);

Uri[] uris = responseImages.Select(x => new Uri(x.image, UriKind.Absolute)).ToArray();