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How use the Byte Array of a image?

So, i am getting the byte array of a LongRaw image from Oracle...
I am using a webapi to this. After get the array, how i use it on the Client-side ?
Do Its better i convert to base64string and pass this value converting just at the client side ?
cmd.InitialLONGFetchSize = -1;
var reader = cmd.ExecuteReader();
if (reader.Read())
{
// Fetch the LONG RAW
OracleBinary imgBinary = reader.GetOracleBinary(0);
// Get the bytes from the binary obj
byte[] imgBytes = imgBinary.IsNull ? null : imgBinary.Value;
//var imgString = Uri.EscapeDataString(Convert.ToBase64String(imgBytes));
}
//CRIO A LISTA
lretorno.Load(reader, LoadOption.OverwriteChanges, "BUSCAFOTO");
reader.Close();
connection.Close();
connection.Dispose();
var teste = lretorno.Tables[0].AsEnumerable().Select(row => new FotoEnvolvido
{
FOTO = (byte[])(row["FOTO"]),
//FOTO = Convert.ToString(row["FOTO"]),
});
return teste;

You can write a Web API Controller that returns the binary data of an image. Base64 strings impose a overhead of the amount of bytes that have to be transmitted. Please avoid this.
A sample controller can look like this example:
public class WebApiController : ApiController
{
public async Task<HttpResponseMessage> Get(string id)
{
var bytes = await GetBytesFromDataLayerAsync(id);
HttpResponseMessage result = new HttpResponseMessage(HttpStatusCode.OK);
var stream = new MemoryStream(bytes);
result.Content = new StreamContent(stream);
result.Content.Headers.ContentType =
new MediaTypeHeaderValue("image/jpeg");
return result;
}
private async Task<byte[]> GetBytesFromDataLayerAsync(string id)
{
// put your Oracle logic here
return ...
}
}

Depending on what your doing as rboe said writing the bytes directly to the client will save some data size(approx. 37%) and computing overhead. If your not only displaying jpeg images you should also set the mime-type to the correct value... take a look at this source for a rather complete set of extension to mime-type mappings. If you do not know the mime-type you can try "application/octet-stream" as that is the general mime-type for binary data.
If your displaying your content via web browser you could just use an <img> tag something like <img src="view_image.aspx?id=5"> you can even create the dynamically with javascript/jQuery.
If you really do want the image data embedded in a json request which might be useful if you have a lot of little icons and don't want a ton of requests (with http/2 I don't think this will matter) or another reason, then yes first encode the binary data using...
string base64EncodedData = Convert.ToBase64String(bytes);
If the client is javascript you can decode using the latest browsers native functions
var decodedImageData = window.atob(base64EncodedData);
See:
mozilla.org docs
This answer
This answer
If you are however just sending it to another c# endpoint you can use...
byte[] decodedImageData = Convert.FromBase64String(base64EncodedData);
And like I mentioned in the comment to ensure it's encrypted just make the site only support https:// and if you don't have a SSL cert you can get one for free from http://startssl.com

WebApi get the post raw body inside a filter

I' creating a log and i need to retrieve the request body to save in db. i created a filter with HttpActionContext.
I tried recover via filterContext.Request.Content.ReadAsStringAsync().Result;
but it always return me an empty string.
LogFilter.cs
public override void OnActionExecuting(HttpActionContext filterContext)
{
try
{
Task<string> content = filterContext.Request.Content.ReadAsStringAsync();
string body = content.Result;
logModel.RequestLog rl = new logModel.RequestLog();
rl.IP = ((HttpContextWrapper)filterContext.Request.Properties["MS_HttpContext"]).Request.UserHostAddress;
rl.Type = filterContext.ControllerContext.RouteData.Values["controller"].ToString().ToUpper();
rl.URL = filterContext.Request.RequestUri.OriginalString;
rl.Operation = filterContext.Request.Method.Method;
rl.RequestDate = DateTime.Now;
filterContext.ControllerContext.RouteData.Values.Add("reqID", new deviceLog.RequestLog().Add(rl).ID.ToString());
}
catch { }
//return new deviceLog.RequestLog().Add(rl);
base.OnActionExecuting(filterContext);
}

Maybe request stream already reached to end. Try reset stream position to beginning:
public class MyAttribute:ActionFilterAttribute
{
public override void OnActionExecuted(HttpActionContext actionContext)
{
string rawRequest;
using (var stream = new StreamReader(actionContext.Request.Content.ReadAsStreamAsync().Result))
{
stream.BaseStream.Position = 0;
rawRequest = stream.ReadToEnd();
}
}
}

almost 7 years late... I was tasked to create a filter for a legacy project - about 8 years old - with no patterns or architecture whatsoever.
I tried reading from stream with stream/string async but it doesn't let you read more than once, and it was already read before the action filter - Seek was false, position was readonly.
I tried reflection but it was too much for little gain and again I didn't like it.
I tried getting "MS_HttpContext" but it wasn't in the dictionary.
After 8 hours of research I compromised with getting all the action arguments from the request and just turn them into Json.
For 4.7 framework API:
private string requestBody = "";
public override void OnActionExecuting(HttpActionContext actionContext)
{
requestBody = JsonConvert.SerializeObject(actionContext.ActionArguments);
base.OnActionExecuting(actionContext);
}
For .NET 5.0:
I use this on OnResultExecuted method. The stream is already read so you need to reposition the request body at 0.
private static async Task<string> FormatRequestBody(HttpRequest request)
{
// we set the stream position to 0 to reset the pointer. If this is not done, the read stream will be incorrect and the Body will be empty
request.Body.Position = 0;
// We now need to read the request stream. First, we create a new byte[] with the same length as the request stream...
var buffer = new byte[Convert.ToInt32(request.ContentLength)];
//...Then we copy the entire request stream into the new buffer.
await request.Body.ReadAsync(buffer, 0, buffer.Length);
// We convert the byte[] into a string using UTF8 encoding...
//... and send it back...
return Encoding.UTF8.GetString(buffer);
}
Hope this helps someone, because I stumbled on this post along with other 15 stackoverflow posts while doing my research.

Streaming large list of data as JSON format using Json.net

Using the MVC model, I would like to write a JsonResult that would stream the Json string to the client rather than converting all the data into Json string at once and then streaming it back to the client.
I have actions that require to send very large (over 300,000 records) as Json transfers and I think the basic JsonResult implementation is not scalable.
I am using Json.net, I am wondering if there is a way to stream the chunks of the Json string as it is being transformed.
//Current implementation:
response.Write(Newtonsoft.Json.JsonConvert.SerializeObject(Data, formatting));
response.End();
//I know I can use the JsonSerializer instead
Newtonsoft.Json.JsonSerializer serializer = new Newtonsoft.Json.JsonSerializer();
serializer.Serialize(textWriter, Data);
However I am not sure how I can get the chunks written into textWriter and write into response and call reponse.Flush() until all 300,000 records are converted to Json.
Is this possible at all?

Assuming your final output is a JSON array and each "chunk" is one item in that array, you could try something like the following JsonStreamingResult class. It uses a JsonTextWriter to write the JSON to the output stream, and uses a JObject as a means to serialize each item individually before writing it to the writer. You could pass the JsonStreamingResult an IEnumerable implementation which can read items individually from your data source so that you don't have them all in memory at once. I haven't tested this extensively, but it should get you going in the right direction.
public class JsonStreamingResult : ActionResult
{
private IEnumerable itemsToSerialize;
public JsonStreamingResult(IEnumerable itemsToSerialize)
{
this.itemsToSerialize = itemsToSerialize;
}
public override void ExecuteResult(ControllerContext context)
{
var response = context.HttpContext.Response;
response.ContentType = "application/json";
response.ContentEncoding = Encoding.UTF8;
JsonSerializer serializer = new JsonSerializer();
using (StreamWriter sw = new StreamWriter(response.OutputStream))
using (JsonTextWriter writer = new JsonTextWriter(sw))
{
writer.WriteStartArray();
foreach (object item in itemsToSerialize)
{
JObject obj = JObject.FromObject(item, serializer);
obj.WriteTo(writer);
writer.Flush();
}
writer.WriteEndArray();
}
}
}

The problem with leaving it up to .NET and wait until the buffer is full has other problems.
For example:
If you do that some of the contents for the json will cut off causing parsing issues on the frontend.
Best approach so far is to flush the batch on each iteration in the event you do use a batch or flush it per single item if that's what your design is for.
Currently i use SSE to push to the data to browser and a delimiter message 'on message end' to indicate to the broswer that the connection can be closed, i know SSE use case is for continuous stream but we can also use it to help with chunking and batching response.

How to get the stream for a Multipart file in webapi upload?

I need to upload a file using Stream (Azure Blobstorage), and just cannot find out how to get the stream from the object itself. See code below.
I'm new to the WebAPI and have used some examples. I'm getting the files and filedata, but it's not correct type for my methods to upload it. Therefore, I need to get or convert it into a normal Stream, which seems a bit hard at the moment :)
I know I need to use ReadAsStreamAsync().Result in some way, but it crashes in the foreach loop since I'm getting two provider.Contents (first one seems right, second one does not).
[System.Web.Http.HttpPost]
public async Task<HttpResponseMessage> Upload()
{
if (!Request.Content.IsMimeMultipartContent())
{
this.Request.CreateResponse(HttpStatusCode.UnsupportedMediaType);
}
var provider = GetMultipartProvider();
var result = await Request.Content.ReadAsMultipartAsync(provider);
// On upload, files are given a generic name like "BodyPart_26d6abe1-3ae1-416a-9429-b35f15e6e5d5"
// so this is how you can get the original file name
var originalFileName = GetDeserializedFileName(result.FileData.First());
// uploadedFileInfo object will give you some additional stuff like file length,
// creation time, directory name, a few filesystem methods etc..
var uploadedFileInfo = new FileInfo(result.FileData.First().LocalFileName);
// Remove this line as well as GetFormData method if you're not
// sending any form data with your upload request
var fileUploadObj = GetFormData<UploadDataModel>(result);
Stream filestream = null;
using (Stream stream = new MemoryStream())
{
foreach (HttpContent content in provider.Contents)
{
BinaryFormatter bFormatter = new BinaryFormatter();
bFormatter.Serialize(stream, content.ReadAsStreamAsync().Result);
stream.Position = 0;
filestream = stream;
}
}
var storage = new StorageServices();
storage.UploadBlob(filestream, originalFileName);**strong text**
private MultipartFormDataStreamProvider GetMultipartProvider()
{
var uploadFolder = "~/App_Data/Tmp/FileUploads"; // you could put this to web.config
var root = HttpContext.Current.Server.MapPath(uploadFolder);
Directory.CreateDirectory(root);
return new MultipartFormDataStreamProvider(root);
}

This is identical to a dilemma I had a few months ago (capturing the upload stream before the MultipartStreamProvider took over and auto-magically saved the stream to a file). The recommendation was to inherit that class and override the methods ... but that didn't work in my case. :( (I wanted the functionality of both the MultipartFileStreamProvider and MultipartFormDataStreamProvider rolled into one MultipartStreamProvider, without the autosave part).
This might help; here's one written by one of the Web API developers, and this from the same developer.

Hi just wanted to post my answer so if anybody encounters the same issue they can find a solution here itself.
here
MultipartMemoryStreamProvider stream = await this.Request.Content.ReadAsMultipartAsync();
foreach (var st in stream.Contents)
{
var fileBytes = await st.ReadAsByteArrayAsync();
string base64 = Convert.ToBase64String(fileBytes);
var contentHeader = st.Headers;
string filename = contentHeader.ContentDisposition.FileName.Replace("\"", "");
string filetype = contentHeader.ContentType.MediaType;
}
I used MultipartMemoryStreamProvider and got all the details like filename and filetype from the header of content.
Hope this helps someone.

ServiceStack: Raw Request Stream

I attempting to read the raw input stream in a ServiceStack Service. I have marked the DTO with IRequiresRequestStream, and the code to read executes, but the content always shows as blank.
Using debug mode in IE9, I can see the raw HttpRequest contains text within the POST as delivered.
Here is my code from a minimal test service intended only to show reading of the content and query:
[Route("/qtest")]
public class QueryTestRequest : IReturn<string>, IRequiresRequestStream
{
public Stream RequestStream { get; set; }
}
public class QueryTestService : Service
{
public string Any(QueryTestRequest request)
{
var r = new StringBuilder();
r.Append("<p>This is the query test service:");
r.AppendFormat("<p>Parameter value={0}", base.Request.QueryString["value"]);
var postStream = new StreamReader(request.RequestStream);
var postContent = postStream.ReadToEnd();
r.AppendFormat("<p>Raw Content={0}", postContent);
return r.ToString();
}
}
What am I missing here?

Yes I find that weird as well, but maybe it's me who doesn't understand the nature of the HttpRequestStream.
Anyway... I managed to get hold of the file using:
var stream = Request.Files[0].InputStream;
And then you can handle that stream.
It appears that more than one file can be uploaded, but I guess that would be difficult to wrap into a REST-framework.