Understanding Long Polling in Web Development

Long polling is a web development technique used to obtain near real-time data from a server. It works by having the client send a request to the server and then keeping that connection open until new data is available or until the connection times out. This differs from short polling, which involves sending requests at regular intervals to check for new data - this will consume more resources due to all of the additional requests sent compared with Long Polling, which only sends one request per update. Comparing both techniques, Long Polling allows for faster response times due to less frequent requests being sent but can be limited in scalability depending on how many connections need to remain open simultaneously.


How Does Long Polling Work

The client initiates a long poll request by making an HTTP GET request to the server. This request is kept open until new data is available or the requests times out, at which point the connection will be closed and a new one opened when needed. The server then responds with any available data in its response, if there is none then it simply keeps the connection open until something becomes available. If no further updates are expected, then the server can close the connection after a certain amount of time has passed without sending any additional responses.

When new data does become available on the server side, it sends back an updated response to each pending long poll request containing all of that information in a single message and closes those connections. Any subsequent requests coming from clients for more recent information will receive this same updated response as soon as they arrive at the server so that they don’t have to wait for additional updates before getting their desired content. This helps ensure faster loading times and allows users to see up-to-date information quickly without having to constantly refresh their page or make multiple requests for each update.


Implementing Long Polling

To implement Long Polling, it is important to choose the right libraries and protocols. The most popular library for this type of development is Socket. io as it provides an easy-to-use API and supports both client-side and server-side JavaScript. Other options include Comet D, which is a more comprehensive framework that can also be used for Long Polling implementations.

When selecting the protocol to use for Long Polling, there are two main ones available: HTTP long polling or Web Socket messaging. Each has its own advantages and disadvantages depending on what kind of data you're sending between clients and servers. With HTTP long polling, you have better control over how often requests are sent, but network latency may cause delays in responses; whereas with Web Socket messaging, communication is bi-directional (allowing messages to be sent back and forth without having to open new connections) but requires more resources from the server due to persistent connection requirements. Ultimately it depends on your specific application needs when deciding which protocol will work best for you!

After selecting the appropriate libraries and desired protocol, the next step is to implement application logic using these tools to create a functioning Long Polling system. This requires setting up event handlers that respond to changes in state on both sides of the connection, allowing updates to be pushed out as needed. It is crucial to consider security measures, including authentication mechanisms and encryption methods, especially when exchanging sensitive data through these channels.


SDKs for Long Polling

An SDK, or Software Development Kit, is a set of tools used for creating applications. They are typically composed of libraries, frameworks and other components that help developers quickly create their software without having to write all the code from scratch. Long Polling is an important concept when it comes to real-time web development, so there are many SDKs available specifically designed for this purpose.

The most popular SDKs for Long Polling include Socket. io and Comet D, both of which provide easy-to-use APIs and support client-side and server-side Java Script respectively. Socket. io allows developers to use both HTTP long polling as well as Web Socket messaging protocols while Comet D offers features such as message routing capabilities and event listening functionality which can be useful in certain scenarios where more control over the data being sent back and forth is necessary. Additionally, these SDKs also offer security features like authentication mechanisms or encryption methods if sensitive data needs to be exchanged during the process of sending updates between clients and servers via Long Polling requests.

For those looking for a more comprehensive solution than what an individual SDK provides on its own, there are also several platform solutions available that allow developers to build their application using multiple different technologies at once – some examples include Pub Nub Data Stream Network (DSN), Firebase Realtime Database, Amazon Kinesis Streams among others. These services provide access to various real-time databases as well as streaming technologies that can facilitate faster response times with low latency by taking advantage of cloud computing resources instead of relying solely on traditional web servers hosted locally at your business premises. This makes them ideal solutions for larger-scale projects where scalability is key!


Using Long Polling with Mobile Apps

Long polling is an effective technique for creating real-time apps that require near-instant communication between the server and mobile devices. When it comes to implementing Long Polling in iOS and Android, there are a few key considerations to keep in mind.

For iOS applications, Apple provides its own API called NSURLSession with support for long polling out of the box. This makes it easy to implement without any third-party libraries or frameworks as all you need to do is configure an NSURLRequest object with the correct parameters and execute it on your app’s background thread. Additionally, if you want more control over how data is sent back from the server then you can use a library like Socket Rocket which adds additional features such as message routing capabilities and event listening functionality specifically designed for this purpose.

On Android, Google has recently released their own solution called Firebase Cloud Messaging (FCM) which allows developers to push notifications directly from their servers using Long Polling requests. FCM also supports up to four different platforms including Android Wear OS as well as web browsers so you can easily send notifications across multiple devices at once with just one request – this makes it ideal for larger-scale projects where scalability is key! Additionally, they offer some advanced features such as automatic scaling based on user engagement so that resources are only used when needed while still providing fast response times even during peak traffic periods.

Overall, both iOS and Android have great solutions available for easily implementing Long Polling within mobile applications regardless of what kind of data needs to be exchanged or how many users will be accessing your app simultaneously – making them great choices when developing real-time experiences that require near instantaneous updates!


Common Pitfalls and Best Practices

Common Pitfalls to Avoid

When implementing Long Polling, there are a few common pitfalls to watch out for. The most important one is not taking into account the latency of the network connection when sending requests or receiving data; if this isn’t taken into account then the user experience may suffer due to delays in responses. Additionally, it’s important to ensure that resources on both sides of the connection are used efficiently and don’t become overburdened – this can be done by limiting how often requests are sent or by using techniques like caching whenever possible. Finally, it’s essential that security measures such as authentication mechanisms or encryption methods are implemented properly so that sensitive data is kept safe while still allowing real-time communication between clients and servers without any disruptions.

Best Practices for Implementing Long Polling

In order to make sure your Long Polling implementation runs smoothly and provides an optimal user experience, there are a few best practices you should follow. Firstly, always test your code thoroughly before deploying it in production so that any issues can be caught early on; secondly, try setting up events handlers with timeout values so that they don't run indefinitely but instead stop after a certain amount of time has passed (this will help prevent server overload); thirdly use persistent connections rather than opening new ones every time data needs to be exchanged as this will reduce overall resource usage significantly; finally keep an eye out for changes in state on either side of the connection as these need to be responded too quickly otherwise updates won't get pushed out correctly!



To enable real-time communication between a server and mobile devices, Long Polling is an advantageous option. Its benefits include low latency responses, easy data accessibility from multiple sources, and improved scalability. However, network latency, resource efficiency, security measures, and timeout values for event handlers should be carefully considered to ensure a seamless experience when implementing Long Polling. To set up infrastructure quickly, SDKs such as Socket.io and Comet D can be used, or for more extensive projects, platform solutions like Pub Nub Data Stream Network (DSN), Firebase Realtime Database, or Amazon Kinesis Streams can be chosen based on requirements. By following these best practices and deploying the application for production, users can interact with the app smoothly without any disruptions.


Fabian Cortez

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