Stories with Tag Server-Sent Events

• You might not need WebSockets

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  Posted: 2025-04-11 22:27:16

  Verbose tl;dr

  The blog post "You might not need WebSockets" argues that developers often prematurely choose WebSockets for real-time features when simpler, more efficient solutions exist. It highlights server-sent events (SSE) as a robust alternative for unidirectional communication from server to client, offering benefits like automatic reconnection and built-in event handling. While acknowledging WebSockets' bi-directional capabilities, the post emphasizes that many use cases only require server-to-client updates, making SSE a lighter and potentially better-performing choice. It encourages developers to carefully analyze their needs before defaulting to WebSockets and consider the reduced complexity and improved resource utilization that SSE can provide.

  The blog post "You might not need WebSockets" argues that while WebSockets offer a persistent, bidirectional communication channel between client and server, they often introduce unnecessary complexity for many web applications. The author contends that simpler, more readily available technologies like HTTP long-polling and server-sent events (SSE) can adequately handle a significant portion of use cases where developers might instinctively reach for WebSockets.

  The core premise is that the perceived need for real-time, instantaneous updates is often a misunderstanding of actual user requirements. In many scenarios, near real-time updates—achieved with a slight delay—are perfectly acceptable and provide a comparable user experience without the overhead of managing WebSocket connections.

  The author elaborates on the challenges associated with WebSockets. These include increased complexity in both client and server implementations, difficulties with scaling due to the persistent nature of the connections, and the potential for increased latency in specific scenarios due to head-of-line blocking (though this can be mitigated). They contrast this with the relative simplicity of HTTP-based solutions.

  Server-Sent Events (SSE) are presented as a compelling alternative for scenarios where the server needs to push updates to the client. SSE leverages a standard HTTP connection, offering a lightweight solution for one-way communication. The author emphasizes the ease of implementation and inherent efficiency of SSE compared to WebSockets.

  Long-polling is discussed as another viable option, particularly when bidirectional communication is required. While acknowledging the limitations of long-polling, such as the potential for increased latency and resource consumption compared to WebSockets under high-load conditions, the author argues that its simplicity can outweigh these drawbacks in less demanding applications. It's presented as a useful stepping stone before resorting to the complexity of WebSockets.

  The article further delves into specific scenarios and provides practical guidance on choosing the appropriate technology. It encourages developers to carefully consider their actual needs and evaluate whether the benefits of WebSockets truly outweigh the costs. The author concludes by recommending a tiered approach, starting with simpler solutions like SSE or long-polling and only escalating to WebSockets when absolutely necessary, emphasizing that premature optimization is often counterproductive. They advocate for choosing the simplest tool that effectively addresses the problem at hand.

  • WebSockets
  • HTTP
  • Server-Sent Events
  • SSE
  • Real-time
  • Web Development
  • performance
  • Alternatives to WebSockets
  • Polling
  • long polling
  • complexity
  • Over-engineering
  • network protocols

  Summary of Comments ( 228 )
  https://news.ycombinator.com/item?id=43659370

  Verbose tl;dr

  HN commenters largely agree with the author's premise that WebSockets are often overused for real-time updates when simpler solutions like HTTP long-polling or Server-Sent Events (SSE) would suffice. Several pointed out the added complexity of WebSockets, both in implementation and infrastructure, with one commenter noting the difficulty in scaling WebSocket connections. The benefits of SSE, particularly its simplicity and native browser support, were highlighted. Some suggested that the choice depends heavily on the specific use case, with WebSockets being more suitable for highly interactive applications like online games, while others argued that even these could be served efficiently with alternatives. A few commenters mentioned the advantages of WebSockets in terms of lower latency and bi-directional communication, but these were generally seen as niche benefits that don't justify the added complexity for most applications. The general consensus seemed to be: consider simpler options first, and only reach for WebSockets when absolutely necessary.

  The Hacker News post "You might not need WebSockets" (https://news.ycombinator.com/item?id=43659370) sparked a discussion with several insightful comments. Many commenters agreed with the author's premise that WebSockets are often overused for real-time updates when simpler solutions like HTTP long-polling or Server-Sent Events (SSE) would suffice.

  One compelling argument highlighted the added complexity introduced by WebSockets, including connection management, reconnection logic, and handling various edge cases. Commenters pointed out that this complexity can lead to increased development time and potentially more bugs, especially for smaller projects or less experienced developers. They argued that unless bidirectional communication is absolutely necessary, the simpler alternatives are preferable.

  Several users shared their personal experiences where they successfully replaced WebSockets with SSE or long-polling, resulting in improved performance and simplified codebases. They emphasized the importance of evaluating the actual requirements before opting for WebSockets.

  The discussion also touched upon the performance aspects of each approach. While some argued that WebSockets offer lower latency, others contended that the difference is negligible for many applications, and the overhead introduced by WebSockets can sometimes negate its theoretical advantages. The point was made that the latency introduced by network conditions often dwarfs the differences between these technologies.

  Another key takeaway from the comments is the importance of considering the specific use case. For chat applications or highly interactive games, WebSockets might be the best choice. However, for applications that primarily involve server-pushed updates, like stock tickers or notification systems, SSE or long-polling are often more suitable.

  A few commenters mentioned the better browser compatibility of SSE and long-polling compared to WebSockets, although this is less of a concern in modern web development.

  Overall, the comments on the Hacker News post generally supported the article's claim that WebSockets are often unnecessarily complex and that simpler alternatives should be considered first. The discussion provided practical advice and real-world examples to help developers make informed decisions about the best technology for their real-time applications.

• Patterns for Building Realtime Features

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  Posted: 2025-02-10 19:42:02

  Verbose tl;dr

  This post explores architectural patterns for adding realtime functionality to web applications. It covers techniques ranging from simple polling and long-polling to more sophisticated approaches like Server-Sent Events (SSE) and WebSockets. The author emphasizes choosing the right tool for the job based on factors like data volume, connection latency, and server resource constraints. They also discuss the importance of considering connection management, message ordering, and error handling. The post provides practical advice and code examples using JavaScript and Node.js to illustrate the different patterns, highlighting their strengths and weaknesses. Ultimately, it aims to give developers a clear understanding of the available options for building realtime features and empower them to make informed decisions based on their specific needs.

  Zach Nilles' blog post, "Patterns for Building Realtime Features," explores various architectural approaches for incorporating realtime functionality into web applications. The post begins by highlighting the increasing demand for realtime experiences, driven by user expectations shaped by applications like Figma and Google Docs. It then emphasizes the importance of carefully choosing the right realtime solution, as different approaches offer varying trade-offs in terms of complexity, scalability, and performance.

  The post categorizes realtime solutions into four primary patterns: request-response with polling, WebSockets, server-sent events (SSE), and third-party services.

  Request-response with polling is presented as the simplest approach. It involves the client repeatedly sending requests to the server to check for updates. While easy to implement, this method can be inefficient due to the overhead of frequent requests and the potential for latency. The post discusses different polling strategies, including short polling (fixed intervals) and long polling (holding the connection open until data is available). Limitations like increased server load and potential for wasted requests are also acknowledged.

  WebSockets are described as providing true bidirectional communication between the client and server. This persistent connection allows for immediate data transfer in both directions, reducing latency and improving efficiency compared to polling. The post details the WebSocket handshake process and emphasizes the benefits of lower latency and reduced overhead. However, it also mentions the increased complexity of managing WebSocket connections and the potential challenges with scaling to a large number of users.

  Server-sent events (SSE) are positioned as a simpler alternative to WebSockets when only server-to-client communication is required. The post explains how SSE utilizes a single HTTP connection for the server to push updates to the client as they become available. This is portrayed as being less complex than WebSockets while still offering significant performance improvements over polling. The unidirectional nature of SSE is highlighted as both a limitation and a simplifying factor, making it suitable for scenarios like live updates or notifications where client-to-server communication isn't necessary.

  Finally, third-party services are introduced as a viable option for offloading the complexity of managing realtime infrastructure. Services like Pusher, Ably, and Firebase are mentioned as examples that provide pre-built solutions for handling realtime communication, scaling, and other related challenges. The post acknowledges the potential cost and vendor lock-in associated with these services, but also highlights the benefits of reduced development time and access to specialized expertise.

  The post concludes by reiterating the importance of choosing the right pattern based on the specific requirements of the application. It advises considering factors such as the frequency of updates, the volume of data, the direction of communication, and the development resources available when making a decision. It encourages readers to thoroughly evaluate the trade-offs of each approach to ensure optimal performance and scalability for their realtime features.

  • realtime
  • Web Development
  • Software Architecture
  • design patterns
  • Backend Development
  • Frontend Development
  • websocket
  • Server-Sent Events
  • long polling
  • push notifications
  • streaming
  • data synchronization
  • concurrency
  • scalability

  Summary of Comments ( 11 )
  https://news.ycombinator.com/item?id=43004334

  Verbose tl;dr

  HN users generally praised the article for its clear explanations and practical approach to building realtime features. Several commenters highlighted the value of the "pull vs. push" breakdown and the discussion of different polling strategies. Some questioned the long-term viability of polling-based solutions and advocated for WebSockets or server-sent events for true real-time experiences. A few users shared their own experiences and preferences with specific technologies like LiveView and Elixir's Phoenix Channels. There was also some discussion about the trade-offs between complexity, performance, and scalability when choosing different realtime approaches.

  The Hacker News post titled "Patterns for Building Realtime Features" (linking to zknill.io/posts/patterns-for-building-realtime/) generated several comments discussing various aspects of implementing real-time functionality.

  Several commenters praised the article for its clear and concise overview of different approaches. One user appreciated the breakdown of techniques, highlighting the comparison between polling, WebSockets, and server-sent events (SSE). They found the discussion of trade-offs, such as the complexity of WebSockets versus the simplicity of SSE, particularly helpful.

  Another commenter focused on the practicality of the information, mentioning how the article helped them understand the reasoning behind choosing one method over another in specific scenarios. They emphasized the value of the article's clear explanations, making it easier for developers to make informed decisions about their real-time implementations.

  The discussion also touched upon the nuances of specific technologies. One comment delved into the benefits of using a message queue like Redis, especially when scaling real-time features. They explained how a message queue can decouple components and improve the overall robustness of the system. Another user mentioned their preference for using a "pushpin" setup for smaller projects due to its ease of use. This sparked a brief side discussion about the advantages and limitations of using simpler tools versus more complex message queues depending on project scale and requirements.

  Furthermore, there was a comment highlighting the importance of considering the client-side implementation alongside the server-side techniques discussed in the article. This commenter pointed out the complexities that can arise when managing client-side state and subscriptions, and suggested looking into libraries and frameworks designed to simplify these tasks.

  While mostly positive, some comments also offered constructive criticism. One commenter noted that the article could have included a deeper discussion of the challenges and potential pitfalls of each approach, such as handling connection interruptions or dealing with high message volumes.

  Overall, the comments section generally praised the article's clarity and practical advice on implementing real-time features. Commenters appreciated the comparison of various techniques and the insights into their respective strengths and weaknesses. The discussion expanded on the article's points by sharing personal experiences, offering alternative tools, and highlighting important considerations for real-world applications.

• The hidden complexity of scaling WebSockets

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  Posted: 2025-01-24 19:48:51

  Verbose tl;dr

  Scaling WebSockets presents challenges beyond simply scaling HTTP. While horizontal scaling with multiple WebSocket servers seems straightforward, managing client connections and message routing introduces significant complexity. A central message broker becomes necessary to distribute messages across servers, introducing potential single points of failure and performance bottlenecks. Various approaches exist, including sticky sessions, which bind clients to specific servers, and distributing connections across servers with a router and shared state, each with tradeoffs. Ultimately, choosing the right architecture requires careful consideration of factors like message frequency, connection duration, and the need for features like message ordering and guaranteed delivery. The more sophisticated the features and higher the performance requirements, the more complex the solution becomes, involving techniques like sharding and clustering the message broker.

  The Compose blog post, "The hidden complexity of scaling WebSockets," delves into the multifaceted challenges inherent in scaling WebSocket connections, going beyond the often-cited limitations of open file descriptors. While acknowledging the importance of managing file descriptors, the article emphasizes that the real bottlenecks frequently lie elsewhere, particularly within the application logic and the infrastructure supporting it.

  The article begins by setting the stage, explaining that WebSockets, unlike traditional HTTP requests, establish persistent, bidirectional communication channels between client and server. This persistent nature creates a long-lived state on the server for each connection, which in turn introduces complexities around managing that state effectively and efficiently at scale.

  One major challenge highlighted is the consumption of server resources. Each open WebSocket connection consumes resources like memory and CPU, not just for the connection itself but also for any associated data structures and processing required to maintain the connection and handle incoming/outgoing messages. As the number of connections increases linearly, so too does the demand on these resources, potentially leading to performance degradation or even server crashes if not properly managed. This is exacerbated by the fact that WebSockets are often used for real-time applications, which typically involve more frequent data exchange and processing than traditional HTTP.

  Furthermore, the article discusses the difficulties of horizontal scaling with WebSockets. While adding more servers can theoretically handle more connections, the persistent nature of WebSockets makes distributing these connections across multiple servers complex. Maintaining consistent state across all servers and ensuring messages reach the correct client, regardless of which server they are connected to, necessitates implementing more sophisticated routing and load balancing mechanisms. These mechanisms themselves introduce additional overhead and complexity.

  The post also underscores the importance of message delivery guarantees. Unlike HTTP, where the request-response cycle provides inherent acknowledgement, guaranteeing message delivery with WebSockets requires implementing application-level acknowledgement and potentially message queuing mechanisms. This adds another layer of complexity, especially in distributed environments where message ordering and delivery across multiple servers must be considered.

  Finally, the article touches upon the operational complexities of managing a large-scale WebSocket infrastructure. Monitoring the health of connections, handling connection failures gracefully, and troubleshooting issues in a real-time environment present significant challenges. Efficient logging, metrics collection, and debugging tools are crucial for maintaining a stable and performant system.

  In conclusion, the article argues that scaling WebSockets is not simply a matter of increasing file descriptor limits. It requires careful consideration of resource consumption, horizontal scaling strategies, message delivery guarantees, and the overall operational complexity of managing a large, distributed, real-time system. These complexities necessitate a more holistic approach that goes beyond basic connection management and addresses the underlying architectural and operational challenges.

  • WebSockets
  • Scaling
  • WebSocket Scaling
  • WebSockets Architecture
  • Real-time Applications
  • performance
  • concurrency
  • distributed systems
  • Network Programming
  • Software Architecture
  • High Availability
  • Horizontal Scaling
  • Vertical Scaling
  • Load Balancing
  • message queues
  • Publish/Subscribe
  • Web Development
  • Backend Development
  • Server-Sent Events

  Summary of Comments ( 15 )
  https://news.ycombinator.com/item?id=42816359

  Verbose tl;dr

  HN commenters discuss the challenges of scaling WebSockets, agreeing with the article's premise. Some highlight the added complexity compared to HTTP, particularly around state management and horizontal scaling. Specific issues mentioned include sticky sessions, message ordering, and dealing with backpressure. Several commenters share personal experiences and anecdotes about WebSocket scaling difficulties, reinforcing the points made in the article. A few suggest alternative approaches like server-sent events (SSE) for simpler use cases, while others recommend specific technologies or architectural patterns for robust WebSocket deployments. The difficulty in finding experienced WebSocket developers is also touched upon.

  The Hacker News post "The hidden complexity of scaling WebSockets" (https://news.ycombinator.com/item?id=42816359) has several comments discussing the challenges and nuances of scaling WebSocket connections.

  Several commenters highlight the often underestimated operational burden of maintaining a WebSocket infrastructure. One user points out that while WebSockets are conceptually simple, the reality of managing thousands or millions of persistent connections introduces significant complexity in terms of infrastructure, monitoring, and debugging. They mention that this operational overhead is often overlooked in the initial design phase.

  Another commenter emphasizes the importance of horizontal scaling for WebSocket servers. They suggest that traditional load balancing techniques commonly used for HTTP requests are not always directly applicable to WebSockets due to the persistent nature of the connections. This requires specialized load balancers or proxy servers that can effectively distribute WebSocket traffic across multiple server instances while maintaining connection affinity.

  The discussion also touches upon the difficulties of handling connection disruptions and reconnections. One user shares their experience of building a real-time application with WebSockets and the challenges faced in ensuring seamless reconnection in various network scenarios, including temporary network outages or client device mobility.

  A few commenters delve into the technical details of different WebSocket scaling solutions. They mention technologies like Redis Pub/Sub and distributed message queues like Kafka as potential approaches for handling large-scale WebSocket deployments. They also discuss the trade-offs between various scaling strategies, such as using a single, large WebSocket server versus distributing the load across multiple smaller servers.

  A recurring theme in the comments is the need for robust monitoring and logging for WebSocket infrastructure. Users highlight the importance of tracking key metrics like connection counts, message throughput, and latency to identify potential bottlenecks and performance issues.

  One commenter mentions the challenge of managing backpressure when the message rate exceeds the server's processing capacity. They suggest employing strategies like rate limiting or message queuing to prevent overload and ensure system stability.

  Finally, some comments discuss the alternative approaches to WebSockets, such as Server-Sent Events (SSE) and long-polling. They mention that while WebSockets offer bidirectional communication, SSE might be a simpler and more efficient solution for certain use cases where only server-to-client communication is required.