@juntoz/koa-require-header/index.js

Koa middleware to require an http header and write to state variable

const { camelCase } = require('change-case');

function _defaultOptions() {
    return {
        headerName: null,
        stateName: null,
        ifNotFound: 'throw', // throw, ignore
        ignorePaths: []
    };
}

function setup(options) {
    options = Object.assign(_defaultOptions(), options);

    if (!options.ignorePaths) {
        options.ignorePaths = [];
    }

    if (!options.stateName) {
        // convert e.g. X-FORWARD-IP to xForwardIp
        options.stateName = camelCase(options.headerName);
    }

    return async(ctx, next) => {
        if (options.headerName && !options.ignorePaths.includes(ctx.path)) {
            // NOTE: it seems HTTP brings headers always in uppercase, yet the header object puts them all in lower case
            var headerValue = ctx.header[options.headerName.toLowerCase()];

            if (!headerValue && options.ifNotFound === 'throw') {
                ctx.throw(400, `${options.headerName} is required`);
            }

            if (headerValue && options.stateName) {
                ctx.state[options.stateName] = headerValue;
            }
        }

        await next();
    };
}

module.exports = setup;