Body size limiting

This page is based on the following example:

https://github.com/aileron-gateway/aileron-gateway/tree/main/examples/bodylimit/

Body Limit Middleware

Overview

This example shows request body size limiting.

block-beta
  columns 5
  Downstream:1
  space:1
  block:aileron:3
    HTTPServer["🟪</br>HTTP</br>Server"]
    BodyLimitMiddleware["🟩</br>BodyLimit</br>Middleware"]
    EchoHandler["🟥</br>Echo</br>Handler"]
  end

Downstream --> HTTPServer
HTTPServer --> Downstream

style Downstream stroke:#888
style EchoHandler stroke:#ff6961,stroke-width:2px
style BodyLimitMiddleware stroke:#77dd77,stroke-width:2px

Legend:

• 🟥 #ff6961 Handler resources.
• 🟩 #77dd77 Middleware resources (Server-side middleware).
• 🟦 #89CFF0 Tripperware resources (Client-side middleware).
• 🟪 #9370DB Other resources.

In this example, following directory structure and files are supposed. If you need a pre-built binary, download from GitHub Releases.

access-logging/  ----- Working directory.
├── aileron      ----- AILERON Gateway binary (aileron.exe on windows).
└── config.yaml  ----- AILERON Gateway config file.

Config

Configuration yaml to run a server with access logging becomes as follows.

# config.yaml

apiVersion: core/v1
kind: Entrypoint
spec:
  runners:
    - apiVersion: core/v1
      kind: HTTPServer

---
apiVersion: core/v1
kind: HTTPServer
spec:
  addr: ":8080"
  virtualHosts:
    - middleware:
        - apiVersion: app/v1
          kind: BodyLimitMiddleware
      handlers:
        - handler:
            apiVersion: app/v1
            kind: EchoHandler

---
apiVersion: app/v1
kind: EchoHandler

---
apiVersion: app/v1
kind: BodyLimitMiddleware
spec:
  maxSize: 10 # bytes
  memLimit: 5 # bytes
  tempPath: "./"

The config tells:

• Start a HTTPServer with port 8080.
• A echo handler is applied.
• Limit requests body size with BodyLimitMiddleware.

This graph shows the resource dependencies of the configuration.

graph TD
  Entrypoint["🟪 **Entrypoint**</br>default/default"]
  HTTPServer["🟪 **HTTPServer**</br>default/default"]
  EchoHandler["🟥 **EchoHandler**</br>default/default"]
  BodyLimitMiddleware["🟩 **BodyLimitMiddleware**</br>default/default"]

Entrypoint --"Runner"--> HTTPServer
HTTPServer --"HTTP Handler"--> EchoHandler
HTTPServer --"Middleware"--> BodyLimitMiddleware

style EchoHandler stroke:#ff6961,stroke-width:2px
style BodyLimitMiddleware stroke:#77dd77,stroke-width:2px

Run

Run the AILEROn Gateway with the command:

./aileron -f ./config.yaml

Check

First, send HTTP requests with body size <= memLimit (5 bytes). Actual body size will be checked by reading the body on the memory because the body size is less than memLimit.

$ curl http://localhost:8080 -d "12345"

~~~ omit output ~~~

---------- Body ----------
12345
--------------------------

Next, send HTTP requests with body memLimit < size <= maxSize (10 bytes). Actual body size will be checked by reading the body on a file (temporal file will be output to the tempPath).

$ curl http://localhost:8080 -d "1234567890"

~~~ omit output ~~~

---------- Body ----------
1234567890
--------------------------

Lastly, send HTTP requests with body maxSize (10 bytes) < size. Because the actual body size exceeds the maxSize, requests should not be allowed.

$ curl http://localhost:8080 -d "12345678901"

{"status":413,"statusText":"Request Entity Too Large"}