Marvel Characters Golang REST Api

A RESTful api that's based on Marvel API that returns:

• all the Marvel character ids in a JSON array of numbers.
• the id, name and description of a character.

Requirements

• Sign up for a free Marvel Developer API at https://developer.marvel.com/.
• Go version 1.15 or greater.
• Install mux router to implement a request router and dispatcher for matching incoming requests to their respective handler.
• Install Go CORS handler to handle cors requests.
• This api is developed and verified in Ubuntu 18.04.5 LTS

Quick Start

Install this Marvel REST Api

go get -u github.com/albertleng/restapi

Install mux router

go get -u github.com/gorilla/mux

Install CORS handler

go get -u github.com/rs/cors

Environment Variables

To run this project, you will need to add the following environment variables:

MARVEL_API_PRIVATE_KEY

MARVEL_API_PUBLIC_KEY

Build and run the rest api

Run the build.sh to build and run the rest api

./build.sh

or

cd "$GOPATH"/src/github.com/albertleng/restapi || exit
go build -o restapi
echo "Go build done"
./restapi 

Endpoints

Get all Marvel character ids

GET /characters

Get id, name and description of a character

GET /characters/{characterId}

Tests

main_test.go contains tests for /characters and /characters/{characterId}.

# run test
go test -v

Caching Strategy

This api uses a simple text file ids.txt to store the character ids.

In response to a /characters call, there will be two scenarios:

1. ids.txt exists

The api reads all the character ids from ids.txt into an integer array, ids.

• If it is the first call after the api starts, the api makes calls to https://gateway.marvel.com/v1/public/characters with offset starting with length of ids (and increment of 100 in subsequent calls) and limit of 100 until there is no character returned. These character ids are appended to both ids.txt and ids. The updated ids is returned as a response to the caller. (Notes: the calls to https://gateway.marvel.com/v1/public/characters are to account for the fact that there were new Marvel character(s) added where are not in ids.txt)
• If it is not the first call after the api starts, the api returns ids as a response to the caller.

2. ids.txt does not exist

The api makes calls to https://gateway.marvel.com/v1/public/characters with offset starting with 0 (and increment of 100 in subsequent calls) and limit of 100 until there is no character returned. In each call, the character ids are appended to an integer array, ids. The file ids.txt is created, and ids is written to ids.txt. The ids is returned as a response to the caller.

Sample content of ids.txt

1011334
1017100
1009144
1010699
1009146
1016823
1009148
1009149
1010903
...

Future Enhancements

• Add caching of id, name and description, read from cache and return it as response to calls to /characters/{characterId} to reduce latency.
• Add TLS/https to encrypt requests and responses.
• Refactor codes for better readability and maintainability.
• Key Improvements:
  • No project structure
  • Caching strategy is not complete. No cache invalidation unless app is restarted.
  • Does not pull data from marvel in parallel which means very slow API call.
  • No error handling, app crashes when sending an invalid character id.
  • Could have made it easier to run by using go mod.
  • No unit testing for cache logic
  • The code structure is not good. No separation of concern, not much abstraction to make it easier to maintain.
  • Caching strategy is not accounting for updated characters.
  • Cache refresh requires app restart.
  • HTTP request is performed sequentially.