Open the Startup. Call the AddCors method on the services object as shown in the following code snippet:. Scroll down within the Startup. Listing 1 shows you the code to add to allow the Web API to accept requests only from localhost Call the app. UseCors method prior to calling the app. UseMvc method. It's a good idea to test out your Web API project and ensure that it accepts requests as expected.
The browser will come up with a blank page. Type the following into the browser address bar:. Press the Enter key to submit the request and you should see a string that looks like the following:.
A file you upload from your local hard drive has attributes that you should transmit to the Web service. These attributes are things like the file name, the file type, the size of the file, etc.
You're going to also add some additional properties to hold the file contents as a Base64 encoded string and a byte array. Add a new file named FileToUpload. Add the code shown in the following code snippet to this file:.
Obviously, you need a controller class to which you send the file. Delete the ValuesController. Add a file named FileUploadController. Add the code shown below to this file:. The above code creates the route for the FileUploadController, sets up a constant with the path to a folder on your local hard drive that your Web project has permissions to write to, and sets up the Post method to which you send an object of the type FileToUpload.
Instead of the hard-coded constant for the file path to write the uploaded file to, you should take advantage of the ASP. NET Core configuration system to store the path. For this article, I wanted to keep the code simple, and used a constant.
Start creating the code within the Post method now. Just above the return Ok ; line, define a new variable named filePathName. Create the full path and file name to store the uploaded file into.
To provide some uniqueness to the file name, add on the current date and time. Remove any characters that aren't valid for a file by using the Replace method. Finish the file name by adding on the file extension from the file object uploaded. If you're going to have multiple users uploading files at the same time, you might also want to add a session ID, a GUID, or the user's name to the file name so you won't get any name collisions. In the Angular code you're going to write, you're going to be reading the file from the file system using the FileReader class.
This class is only available on newer browsers. The FileReader class reads the file from disk as a Baseencoded string. At the beginning of this Baseencoded string is the type of file read from the disk followed by a comma.
The rest of the file contents are after the comma. Next is a sample of what the contents of the file uploaded look like. Write the following code to strip off the file type. Check to ensure that the file type is there so you don't get an error by passing a negative number to the Substring method. Don't store the file uploaded as a Baseencoded string. You want the file to be useable on the server just like it was on the user's hard drive.
Convert the file data into a byte array using the FromBase64String method on the. NET Convert class. You're finally ready to write the file to disk on your server. Create a new FileStream object and pass the byte array to the Write method of this method.
Pass in a zero as the second parameter and the length of the byte array as the third parameter so the complete file is written to disk.
I've purposefully left out any error handling, but you should add some into this method. The current virtual directory is used to obtain the file using the filename parameter. The file is opened as a BinaryReader type with Read access. The total bytes of the file are stored to a local variable of type byte[] - a byte array. The file stream is closed, and the Web method returns the byte array. The PutFile method accepts a byte array, buffer , and a string, filename.
A file with the name filename is created as a BinaryWriter type with ReadWrite access. The byte array is written to the file stream and the file stream is closed. Now test the code by navigating to the. You should be prompted with links to the two Web methods. Then, test the GetFile method. Enter a file name that you know exists on the virtual root of the Web service application.
Click on the Invoke button, and you'll see the base64 encoded string of the file contents. Set the Output Directory to the same directory as your Web service virtual root and then generate the proxy. Create a new ASP.
NET Web page. Add the following code to your new page:. SaveAs filename ; System. BinaryReader System. Open filename, System. Open, System. The only requirement for accessing a service is an internet connection to make the HTTP request. Since a web service is cross-platform, there should be some commonly understandable language for requesting a service and getting a response from the service.
Such a standard common language is XML. As a result, the set of data types Web Services can use is limited to the set of data types recognized by the XML Schema standard.
So you can use simple data types such as strings and numbers to communicate with a web service and you can't send proprietary. This restriction makes a lot of sense. Since other programming languages have no way to interpret these. NET objects, even if you could devise a way to send them over the wire, the client might not be able to interpret them, that would thwart interoperability. Note 3: If you need to work with. NET proprietary objects, you can go for.
NET remoting. It is a distributed technology that allows use of. NET objects. But non-. NET clients can't consume it. Here I will use Visual Studio though you can use any editor , with the.
Net Framework 3. Up to framework 3. Open Visual Studio in Administrator mode. Visual Studio will create a web service boilerplate Service1. Now, let's analyze this template created by Visual Studio. Now let's see the mark up. Right-click on Service1. In Service1. So the asmx page has no mark up. You will find a link for Service Description, that will redirect to the WSDL document of the service, another link for HelloWorld list for methods exposed by service that will redirect to a page for testing this method.
Now let's implement the service. Change the class name from Service1 to MyService. Open the mark up asmx page. So Visual Studio is unable to resolve it. Let's run the project by hitting F5. Let's use method overloading of the OOP concept. Add the following WebMethod in MyService class.
Use the MessageName property of the WebMethod custom attribute to specify unique message names for the methods. We just used method overloading concept, so why this error message? This is because these methods are not unique for a client application.
As the error message suggests let's use the MessageName property of the WebMethod attribute as shown below:.
Now , compile and run the application. As, WsiProfiles. Let's work to help developers, not make them feel stupid. Related Questions. Consume odata web api with a HttpClient. Status code when I post data using web api in winforms C. Error arduino no matching function for call to : httpclient:httpclient. How do I begin sending a post message to a webapi using httpclient in C? I want to use webclient instead of httpclient. Httpclient return badrequest alsways couldnt understand the issue.
How do i NET with xamarin httpclient. Layout: fixed fluid.
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