feat: allow enabling and disabling compression and decompression separately

Author: Aeolun

README.md

@@ -56,6 +56,17 @@ await fastify.register(
   { global: false }
 )
 ```
+
+If only compression, or only decompression is desired, you can use the `globalCompression` or `globalDecompression` config flags to turn either off specifically (because the global hook is enabled by default).
+
+```js
+await fastify.register(
+  import('@fastify/compress'),
+  // only decompress compressed incoming requests
+  { globalCompression: false }
+)
+```
+
 Fastify encapsulation can be used to set global compression but run it only in a subset of routes by wrapping them inside a plugin.
 
 > ℹ️ Note: If using `@fastify/compress` plugin together with `@fastify/static` plugin, `@fastify/compress` must be registered (with *global hook*) **before** registering `@fastify/static`.

index.js

@@ -124,7 +124,9 @@ function processCompressParams (opts) {
   }
 
   const params = {
-    global: (typeof opts.global === 'boolean') ? opts.global : true
+    global: (typeof opts.globalCompression === 'boolean')
+      ? opts.globalCompression
+      : (typeof opts.global === 'boolean') ? opts.global : true
   }
 
   params.removeContentLengthHeader = typeof opts.removeContentLengthHeader === 'boolean' ? opts.removeContentLengthHeader : true
@@ -173,7 +175,9 @@ function processDecompressParams (opts) {
   const customZlib = opts.zlib || zlib
 
   const params = {
-    global: (typeof opts.global === 'boolean') ? opts.global : true,
+    global: (typeof opts.globalDecompression === 'boolean')
+      ? opts.globalDecompression
+      : (typeof opts.global === 'boolean') ? opts.global : true,
     onUnsupportedRequestEncoding: opts.onUnsupportedRequestEncoding,
     onInvalidRequestPayload: opts.onInvalidRequestPayload,
     decompressStream: {

test/global-compress.test.js

@@ -3298,3 +3298,152 @@ for (const contentType of notByDefaultSupportedContentTypes) {
     t.assert.equal(response.rawPayload.toString('utf-8'), file)
   })
 }
+
+test('It should support separate globalCompression and globalDecompression settings', async (t) => {
+  t.plan(3)
+
+  // Test case: disable compression but enable decompression globally
+  const fastify = Fastify()
+  await fastify.register(compressPlugin, {
+    globalCompression: false,
+    globalDecompression: true
+  })
+
+  const testData = { message: 'test data for decompression only' }
+
+  fastify.get('/', (request, reply) => {
+    reply.send(testData)
+  })
+
+  // Test that compression is disabled
+  const getResponse = await fastify.inject({
+    url: '/',
+    method: 'GET',
+    headers: {
+      'accept-encoding': 'gzip, deflate, br'
+    }
+  })
+
+  t.assert.equal(getResponse.statusCode, 200)
+  // No compression should happen since globalCompression is false
+  t.assert.equal(getResponse.headers['content-encoding'], undefined)
+  t.assert.deepEqual(getResponse.json(), testData)
+})
+
+test('It should enable decompression when globalDecompression is true', async (t) => {
+  t.plan(2)
+
+  // Test case: enable decompression globally
+  const fastify = Fastify()
+  await fastify.register(compressPlugin, {
+    globalCompression: false,
+    globalDecompression: true
+  })
+
+  // Create a compressed request payload to test decompression
+  const compressedPayload = zlib.gzipSync(JSON.stringify({ input: 'compressed data' }))
+
+  fastify.post('/', (request, reply) => {
+    // This should be decompressed automatically
+    reply.send({ received: request.body })
+  })
+
+  // Test that decompression is enabled
+  const postResponse = await fastify.inject({
+    url: '/',
+    method: 'POST',
+    headers: {
+      'content-encoding': 'gzip',
+      'content-type': 'application/json'
+    },
+    payload: compressedPayload
+  })
+
+  t.assert.equal(postResponse.statusCode, 200)
+  // Decompression should work since globalDecompression is true
+  t.assert.deepEqual(postResponse.json(), { received: { input: 'compressed data' } })
+})
+
+test('It should fall back to global option when specific options are not provided', async (t) => {
+  t.plan(2)
+
+  // Test that global: false affects both compression and decompression
+  const fastify = Fastify()
+  await fastify.register(compressPlugin, {
+    global: false
+  })
+
+  const testData = { message: 'test data' }
+
+  fastify.get('/', (request, reply) => {
+    reply.send(testData)
+  })
+
+  const response = await fastify.inject({
+    url: '/',
+    method: 'GET',
+    headers: {
+      'accept-encoding': 'gzip, deflate, br'
+    }
+  })
+
+  t.assert.equal(response.statusCode, 200)
+  // No compression should happen since global is false
+  t.assert.equal(response.headers['content-encoding'], undefined)
+})
+
+test('It should demonstrate globalCompression overrides global setting', async (t) => {
+  t.plan(2)
+
+  // Test that globalCompression: true overrides global: false
+  const fastify = Fastify()
+  await fastify.register(compressPlugin, {
+    global: false,
+    globalCompression: true,
+    threshold: 0
+  })
+
+  fastify.get('/', (request, reply) => {
+    reply.send({ message: 'globalCompression overrides global' })
+  })
+
+  const response = await fastify.inject({
+    url: '/',
+    method: 'GET',
+    headers: { 'accept-encoding': 'gzip' }
+  })
+
+  t.assert.equal(response.statusCode, 200)
+  t.assert.equal(response.headers['content-encoding'], 'gzip') // Compression enabled despite global: false
+})
+
+test('It should demonstrate globalDecompression controls decompression independently', async (t) => {
+  t.plan(2)
+
+  // Test globalDecompression: false disables decompression even with global: true
+  const fastify = Fastify()
+  await fastify.register(compressPlugin, {
+    global: true,
+    globalDecompression: false
+  })
+
+  const compressedPayload = zlib.gzipSync(JSON.stringify({ test: 'decompression' }))
+
+  fastify.post('/', (request, reply) => {
+    reply.send({ received: request.body })
+  })
+
+  const response = await fastify.inject({
+    url: '/',
+    method: 'POST',
+    headers: {
+      'content-encoding': 'gzip',
+      'content-type': 'application/json'
+    },
+    payload: compressedPayload
+  })
+
+  // Should get 400 error since decompression is disabled and compressed data can't be parsed
+  t.assert.equal(response.statusCode, 400)
+  t.assert.ok(response.body.includes('Content-Length') || response.body.includes('Bad Request'))
+})

types/index.d.ts

@@ -77,6 +77,8 @@ declare namespace fastifyCompress {
     encodings?: EncodingToken[];
     forceRequestEncoding?: EncodingToken;
     global?: boolean;
+    globalDecompression?: boolean;
+    globalCompression?: boolean;
     inflateIfDeflated?: boolean;
     onInvalidRequestPayload?: (encoding: string, request: FastifyRequest, error: Error) => Error | undefined | null;
     onUnsupportedEncoding?: (encoding: string, request: FastifyRequest, reply: FastifyReply) => string | Buffer | Stream;