test-server

test-server is your new project powered by Ktor framework.

Company website: test.com.nickcipollo Ktor Version: 1.5.2 Kotlin Version: 1.4.10 BuildSystem: Gradle with Kotlin DSL

Ktor Documentation

Ktor is a framework for quickly creating web applications in Kotlin with minimal effort.

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Selected Features:

Routing

Routing Documentation (JetBrains)

Allows to define structured routes and associated handlers.

Description

Routing is a feature that is installed into an Application to simplify and structure page request handling. This page explains the routing feature. Extracting information about a request, and generating valid responses inside a route, is described on the requests and responses pages.

    get("/") {
        call.respondText("Hello, World!")
    }
    get("/bye") {
        call.respondText("Good bye, World!")
    }

get, post, put, delete, head and options functions are convenience shortcuts to a flexible and powerful routing system. In particular, get is an alias to route(HttpMethod.Get, path) { handle(body) }, where body is a lambda passed to the get function.

Usage

Routing Tree

Routing is organized in a tree with a recursive matching system that is capable of handling quite complex rules for request processing. The Tree is built with nodes and selectors. The Node contains handlers and interceptors, and the selector is attached to an arc which connects another node. If selector matches current routing evaluation context, the algorithm goes down to the node associated with that selector.

Routing is built using a DSL in a nested manner:

route("a") { // matches first segment with the value "a"
  route("b") { // matches second segment with the value "b"
     get {…} // matches GET verb, and installs a handler
     post {…} // matches POST verb, and installs a handler
  }
}

method(HttpMethod.Get) { // matches GET verb
   route("a") { // matches first segment with the value "a"
      route("b") { // matches second segment with the value "b"
         handle { … } // installs handler
      }
   }
}
```kotlin
route resolution algorithms go through nodes recursively discarding subtrees where selector didn't match.

Builder functions:
* `route(path)` – adds path segments matcher(s), see below about paths
* `method(verb)` – adds HTTP method matcher.
* `param(name, value)` – adds matcher for a specific value of the query parameter
* `param(name)` – adds matcher that checks for the existence of a query parameter and captures its value
* `optionalParam(name)` – adds matcher that captures the value of a query parameter if it exists
* `header(name, value)` – adds matcher that for a specific value of HTTP header, see below about quality

## Path
Building routing tree by hand would be very inconvenient. Thus there is `route` function that covers most of the use cases in a simple way, using path.

`route` function (and respective HTTP verb aliases) receives a `path` as a parameter which is processed to build routing tree. First, it is split into path segments by the `/` delimiter. Each segment generates a nested routing node.

These two variants are equivalent:

```kotlin
route("/foo/bar") { … } // (1)

route("/foo") {
   route("bar") { … } // (2)
}

Parameters

Path can also contain parameters that match specific path segment and capture its value into parameters properties of an application call:

get("/user/{login}") {
   val login = call.parameters["login"]
}

When user agent requests /user/john using GET method, this route is matched and parameters property will have "login" key with value "john".

Optional, Wildcard, Tailcard

Parameters and path segments can be optional or capture entire remainder of URI.

{param?} –- optional path segment, if it exists it's captured in the parameter
* –- wildcard, any segment will match, but shouldn't be missing
{...} –- tailcard, matches all the rest of the URI, should be last. Can be empty.
{param...} –- captured tailcard, matches all the rest of the URI and puts multiple values for each path segment into parameters using param as key. Use call.parameters.getAll("param") to get all values.

Examples:

get("/user/{login}/{fullname?}") { … }
get("/resources/{path...}") { … }

Quality

It is not unlikely that several routes can match to the same HTTP request.

One example is matching on the Accept HTTP header which can have multiple values with specified priority (quality).

accept(ContentType.Text.Plain) { … }
accept(ContentType.Text.Html) { … }

The routing matching algorithm not only checks if a particular HTTP request matches a specific path in a routing tree, but it also calculates the quality of the match and selects the routing node with the best quality. Given the routes above, which match on the Accept header, and given the request header Accept: text/plain; q=0.5, text/html will match text/html because the quality factor in the HTTP header indicates a lower quality fortext/plain (default is 1.0) .

The Header Accept: text/plain, text/* will match text/plain. Wildcard matches are considered less specific than direct matches. Therefore the routing matching algorithm will consider them to have a lower quality.

Another example is making short URLs to named entities, e.g. users, and still being able to prefer specific pages like "settings". An example would be

https://twitter.com/kotlin -– displays user "kotlin"
https://twitter.com/settings -- displays settings page

This can be implemented like this:

get("/{user}") { … }
get("/settings") { … }

The parameter is considered to have a lower quality than a constant string, so that even if /settings matches both, the second route will be selected.

Options

No options()

Reporting Issues / Support

Please use our issue tracker for filing feature requests and bugs. If you'd like to ask a question, we recommmend StackOverflow where members of the team monitor frequently.

There is also community support on the Kotlin Slack Ktor channel

Reporting Security Vulnerabilities

If you find a security vulnerability in Ktor, we kindly request that you reach out to the JetBrains security team via our responsible disclosure process.

Contributing

Please see the contribution guide and the Code of conduct before contributing.

TODO: contribution of features guide (link)

ncipollo / test-server