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When it comes to choosing the right Swift server-side framework to work with, we shall compare the different frameworks in terms of the several factors that follow:
Since Swift is a compiled language, server-side frameworks written in pure Swift are not necessarily slower than frameworks written in other native programming languages. However, different Swift server-side frameworks may adopt different low-level software stacks or handle events differently.
A collection of benchmarks for popular web frameworks, including both Swift and non-Swift implementations, are documented here: https://medium.com/@codevapor/vapor-3-0-0-released-8356fa619a5d. As we can see, Swift frameworks perform better than most of the web frameworks that are written in interpreted languages such as JavaScript and Python. The benchmarks were based on processing plain text and demonstrated how fast Swift can process HTTP headers. All three Swift server-side frameworks, Vapor, Perfect, and Kitura, are comparable in their performance of plain text processing.
If you are interested in evaluating different aspects of a web framework, for example, the performance for handling routing and parsing path parameters, you can use the Benchmark tool (https://github.com/vapor/benchmarks) to generate specific benchmarks for comparison.
Performance is not the only factor we should consider. A production release of web application includes a complete set of robust features. Swift server-side frameworks often offer many useful functions that are common to most applications. Some common feature sets for Swift frameworks are listed as follows:
When choosing the right server-side framework, we will need to check whether any of the features mentioned have already been integrated in the framework, or if integration of third-party libraries that implement such features are easy and straightforward.
Ecosystem here can be interpreted as the choices of libraries or tools that a Swift server-side adopts and integrates into the framework. We may have preferences for some technologies, and at the same time, we may have reasons for avoiding other technologies as trade-offs in the design of our application. Sometimes, the effort will be daunting if we want to integrate a third-party library into the chosen framework that does not have the library included already. The best time-saving tip is to choose the framework that has the most preferred libraries so we can minimize the effort to do integration ourselves.
The main components and choices of third-party libraries in Vapor and Kitura are listed in the following table:
| Feature | Vapor | Kitura |
|---|---|---|
| OS support | macOS, Linux | macOS, Linux |
| CLI | Vapor Toolbox CLI, Vapor Console API | Kitura CLI, Project Generator |
| Templating engine | Leaf | Stencil, Mustache, Markdown |
| Networking I/O | SwiftNIO | Kitura-NIO (use SwiftNIO and NIOOpenSSL), BlueSocket, Kitura-net |
| ORM | Fluent: SQLite, MySQL, PostgreSQL, Redis | Swift-Kuery-ORM, Swift-Kuery:, PostgreSQL, SQLite, Redis |
| Logging | Logging API, PrintLogger, SwiftyBeaver Logging | LoggerAPI, HeliumLogger |
| Route-type validation | Vapor Validation | n/a |
| Authentication | Turnstile | Kitura-Credentials: HTTP, Facebook, Google, GitHub |
| Security | Vapor-Crypto / SwiftNIO SSL | BlueSSLService |
| User session | SessionMiddleware | Kitura-Session |
| Monitoring & diagnostics | n/a | SwiftMetrics, Health |
| Container | Docker | Docker |
| Orchestration | n/a | Kubernetes / Helm |
| Cloud deployment | Vapor Cloud | IBM Cloud |
In the rest of this book, we will visit most of the previously mentioned technologies again when we learn how to build web applications and services with Vapor and Kitura.
Developer community support is sometimes a deciding factor in the choice of a Swift server-side framework. Strong developer community support means that a framework's feature set is more complete, and there will be enough support when we encounter hurdles in working with the framework.
Vapor enjoys healthy developer community support. Vapor users are well-known for their support and eagerness to help newcomers to Vapor community. There is a lot of activity in social channels. The Vapor community has recently moved their forums from Slack to Discord (http://discord.gg/BnXmVGA). There are also plenty of online learning resources, sample codes, tutorials, books, and community-contributed library plugins available to Vapor users. A word of caution, though: many of the tutorial and learning material for Vapor 2.0 or earlier, are outdated. Due to the substantial changes in Vapor 3.0, especially the migration to asynchronous non-blocking stacks based on SwiftNIO, many of the tutorials need to be revised and updated for Vapor 3.0.
Kitura may have smaller community involvement currently, but IBM's engineers have been active and helpful on GitHub and online forums for new learners of server-side Swift. Kitura has a more complete cloud computing stack. It is easy for users to find the documentation and learning materials for not only the Swift server-side framework but also for other cloud technologies that are often used together with the Swift framework.
Perfect stands out as having extensive tutorials, documentation, and training materials available on its website (https://perfect.org/tutorials.html) for Swift server-side developers. The Perfect framework is more mature, and its learning materials are well-organized. Currently, the Perfect user community has 69 repositories in the Perfect examples (https://github.com/PerfectExamples) repository on GitHub. New Perfect users can use the Slack (http://www.perfect.ly/) channels to interact with other developers and to get help from others.
