Node js downloading file and displaying html/js page

An IP address is a unique sequence of numbers that identify a machine on a network, like the internet. The value localhost is a special private address that computers use to refer to themselves. In our example, we will use port for our web server. Ports and are typically used as default ports in development, and in most cases developers will use them rather than other ports for HTTP servers.

This function must have two arguments, a request object and a response object. The response object is used to return HTTP responses for the server. We want our first server to return this message whenever someone accesses it: "My first server! The function would usually be named based on what it does. For example, if we created a request listener function to return a list of books, we would likely name it listBooks.

Since this one is a sample case, we will use the generic name requestListener. All request listener functions in Node. The HTTP request the user sends is captured in a Request object, which corresponds to the first argument, req. The HTTP response that we return to the user is formed by interacting with the Response object in second argument, res. The first line res. In this case, the status code corresponds to "OK". The next line of the function, res.

This function returns any data the server has to return. After we create our server, we must bind it to a network address. We do that with the server. It accepts three arguments: port , host , and a callback function that fires when the server begins to listen. All of these arguments are optional, but it is a good idea to explicitly state which port and host we want a web server to use.

When deploying web servers to different environments, knowing the port and host it is running on is required to set up load balancing or a DNS alias. The callback function logs a message to our console so we can know when the server began listening to connections. Note: Even though requestListener does not use the req object, it must still be the first argument of the function. With less than fifteen lines of code, we now have a web server.

Notice that the prompt disappears. This is because a Node. It only exits if it encounters an error that causes it to crash and quit, or if we stop the Node. Our Node. The server passed that request to the requestListener function. The function returned text data with the status code The server then sent that response back to cURL, which displayed the message in our terminal.

In most web sites we visit or APIs we use, the server responses are seldom in plain text. In the next step, we will learn how to return HTTP responses in common data formats we encounter in the web. The response we return from a web server can take a variety of formats. Finally, web servers can return non-text data like PDFs, zipped files, audio, and video. The three data types are all text-based, and are popular formats for delivering content on the web.

Many server-side development languages and tools have support for returning these different data types. In the context of Node. The code we will be writing in this section and later ones have many similarities to the code we wrote previously. Most changes exist within the requestListener function.

Create a new file called html. As its name suggests, it is derived from JavaScript objects, but it is language independent, meaning it can be used by any programming language that can parse its syntax. Its popularity is due to lower data transfer size than previous data exchange standards like XML, as well as the tooling that exists that allow programs to parse them without excessive effort. We want to return a JSON response. The res. HTTP headers are additional information that can be attached to a request or a response.

Modify json. Like before, we tell the user that their request was successful by returning a status code of This time in the response. Save and exit json. In most cases, each row is separated by a newline, and each item in the row is separated by a comma.

The second header we add is Content-Disposition. This header tells the browser how to display the data, particularly in the browser or as a separate file. When we return CSV responses, most modern browsers automatically download the file even if the Content-Disposition header is not set. In this case, we signal to the browser that this CSV file is an attachment and should be downloaded.

This time, our call to res. We have two rows, one for the table header and one for the data. Save csv. Its file name will be oceanpals. It was created to structure web content. Once the folder is opened, the option for creating a new file will be displayed to the right, as shown in the following image.

Select the Script folder and click on the new file icon as shown in the following image. This will provide a blank textbox where you create a new file name as app. Add the following markup in it:.

The above code performs the following operations. Note: Comments on each line match with the numbers used in the following points. Since we need to create web server for http messaging, we need http module. We will be reading the html file using File IO, for that we need to load fs module.

If the file is not read successfully, the response with Http Status as Not Found will be sent for the request message. If the file is read, then the html response will be sent back. Step 4: Right-Click on the app.

This will show the command prompt from where we can run the application. This is the default response we have received. This article has been editorially reviewed by Suprotim Agarwal. C and. Organized around concepts, this Book aims to provide a concise, yet solid foundation in C and. NET, covering C 6.

NET Core, with chapters on the latest. NET Core 3. To load the static server files included in the index. The server is running. It is now returning HTML form as a response to the client browser. However, what would happen if you fill this form with the data and press the button subscribe? Reload the page again. Open the browser inspector tool and head to the Network tab. Fill in the form data and click the subscribe button. This will return a status code. This means we are sending a POST request to the server.

Our server does not have a way of processing any POST requests from the client. The server does not give the client POST permission from this route. We can fix this by adding a POST method to the route.

This will handle any POST requests that come from this route. When you click the subscribe button, a Thank you for subscribing message will be printed on the browser. Moreover, the browser will return a code upon checking the inspector network, which is okay.

Everything is working great. Nevertheless, we need the server to get the form data and send the relevant results to the browser instead of sending some relative plain text such as Thank you for subscribing. To interact with the form data, we need a body-parser package.

Go ahead and install this package using npm install body-parser. Body-parser helps parse incoming request bodies in a middleware before your handlers, available under the req.