koa-semver
v1.0.2
Published
Semantic Versioning middleware for Koa
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koa-semver
Match middleware with Semantic Versioning.
Built with npm/node-semver to match familiar npm
style dependency syntax and usage, but for middleware and routes.
Requisites:
Installation
npm install --save koa-semver
# with yarn:
yarn add koa-semver
Usage
koa-semver
allows multiple usage options, but it is strongly recommended to use with koa-router
.
Basic Versioning
A sample Koa server would be:
"use strict";
const Koa = require("koa");
const Router = require("koa-router");
const Semver = require("koa-semver");
const app = new Koa();
const router = new Router();
// Add handlers by priority
// (Descending order)
const ver = new Semver([
Semver.handlers.header("X-Semver"),
Semver.handlers.param(":version"),
Semver.handlers.query("version"),
]);
// Newer middleware or routes should be placed on top
// (Descending order)
router.get("/:version/users", ver.match("~2.10.0", ctx => {
ctx.body = { // Latest
users: {
administrators: [],
clients: [],
},
};
}));
router.get("/:version/users", ver.match("^1.2.0", ctx => {
ctx.body = { // Legacy
users: []
};
}));
app.use(router.routes());
app.listen(3000);
Client side usage:
# Latest version
$ curl http://localhost:3000/_/users
$ curl -H "X-Semver: 2.10.1" http://localhost:3000/_/users
{
"users": {
"administrators": [],
"clients": []
}
}
# Latest version (headers has more priority than route param)
$ curl -H "X-Semver: 2.10.1" http://localhost:3000/1.2.5/users
{
"users": {
"administrators": [],
"clients": []
}
}
# Specific version
$ curl http://localhost:3000/1.3.0/users
$ curl http://localhost:3000/_/users?version=1.4.0
{
"users": []
}
# Unknown version
$ curl http://localhost:3000/3.0.0/users
$ curl http://localhost:3000/0.1.0/users
Not Found
Semver state variable
It is possible to know about the requested and matching versions:
router.get("/:version/users", ver.match("^1.2.0", ctx => {
ctx.body = ctx.state.semver;
}));
Create a matcher
Sometimes we want to reuse the matching version, so we can:
const ver = new Semver();
ver.use(Semver.handlers.header("X-Semver"));
const matcher = ver.matcher("^1.0.0");
const router = new Router();
router.get("/users", matcher(async ctx => {
// ...
}));
router.post("/users/:id/comments", matcher(async ctx => {
// ...
}));
Another way is:
const app = new Koa();
const ver = new Semver();
ver.use(Semver.handlers.header("X-Semver"));
const router = new Router();
router.get("/users", async ctx => {
// ...
});
router.post("/users/:id/comments", async ctx => {
// ...
});
app.use(ver.match("^1.0.0", router.routes()));
Multiple matching
It is responsibility of the developer to stop the middleware propagation. So it is possible to match multiples routes or add conditional middleware using koa-semver
;
const app = new Koa();
const router = new Router();
const ver = new Semver();
ver.use(Semver.handlers.header("X-Semver"));
app.use(ver.match("1.x || >=2.5.0 || 5.0.0 - 7.2.3", (ctx, next) => {
// Patch some buggy versions
ctx.state.something = true;
ctx.body = [];
return next(); // <- Continue middleware chain
}));
router.get("/endpoint", ver.match("^1.2.0", async (ctx, next) => {
ctx.body.append("Hello!");
await next(); // <- Continue middleware chain
}));
router.get("/endpoint", ver.match("^1.1.0", async ctx => {
ctx.body.append("World!");
// We broke the chain
}));
router.get("/endpoint", ver.match("^1.0.1", async ctx => {
// This would never match
}));
// ...
app.use(router.routes());
In this case a GET
request to /endpoint
with X-Semver: 1.2.0
will match the first two routes and will return:
["Hello!", "World!"]
Testing
Run Jest test suite with:
yarn test
# With coverage
yarn test -- --coverage
# Watch for changes
yarn test -- --watch