[微服务架构]API网关.微服务简介，第2部分

/*
* Simple login: returns a JWT if login data is valid.
*/function doLogin(req, res) {
getData(req).then(function(data) { try { var loginData = JSON.parse(data);
User.findOne({ username: loginData.username }, function(err, user) { if(err) {
logger.error(err);
send401(res); return;
} if(user.password === loginData.password) { var token = jwt.sign({ jti: uuid.v4(), roles: user.roles
}, secretKey, { subject: user.username, issuer: issuerStr
});
res.writeHeader(200, { 'Content-Length': token.length, 'Content-Type': "text/plain"
});
res.write(token);
res.end();
} else {
send401(res);
}
}, 'users');
} catch(err) {
logger.error(err);
send401(res);
}
}, function(err) {
logger.error(err);
send401(res);
});
}/*
* Authentication validation using JWT. Strategy: find existing user.
*/function validateAuth(data, callback) { if(!data) {
callback(null); return;
}
data = data.split(" "); if(data[0] !== "Bearer" || !data[1]) {
callback(null); return;
} var token = data[1];
try { var payload = jwt.verify(token, secretKey); //Your custom validation logic goes here.
if(!payload.jti || revokedTokens[payload.jti]) {
logger.debug('Revoked token, access denied: ' + payload.jti);
callback(null);
} else {
callback({jwt: payload});
}
} catch(err) {
logger.error(err);
callback(null);
}
}

/*
* Parses the request and dispatches multiple concurrent requests to each
* internal endpoint. Results are aggregated and returned.
*/function serviceDispatch(req, res) { var parsedUrl = url.parse(req.url);
Service.findOne({ url: parsedUrl.pathname }, function(err, service) { if(err) {
logger.error(err);
send500(res); return;
} var authorized = roleCheck(req.context.authPayload.jwt, service); if(!authorized) {
send401(res); return;
}
// Fanout all requests to all related endpoints.
// Results are aggregated (more complex strategies are possible).
var promises = [];
service.endpoints.forEach(function(endpoint) {
logger.debug(sprintf('Dispatching request from public endpoint ' + '%s to internal endpoint %s (%s)',
req.url, endpoint.url, endpoint.type)); switch(endpoint.type) { case 'http-get': case 'http-post':
promises.push(httpPromise(req, endpoint.url,
endpoint.type === 'http-get')); break; case 'amqp':
promises.push(amqpPromise(req, endpoint.url)); break; default:
logger.error('Unknown endpoint type: ' + endpoint.type);
}
}); //Aggregation strategy for multiple endpoints.
Q.allSettled(promises).then(function(results) { var responseData = {};
results.forEach(function(result) { if(result.state === 'fulfilled') {
responseData = _.extend(responseData, result.value);
} else {
logger.error(result.reason.message);
}
});
res.setHeader('Content-Type', 'application/json');
res.end(JSON.stringify(responseData));
});
}, 'services');
}

var User = userDb.model('User', new mongoose.Schema ({ username: String, password: String, roles: [ String ]
}));var Service = servicesDb.model('Service', new mongoose.Schema ({ name: String, url: String, endpoints: [ new mongoose.Schema({ type: String, url: String
}) ], authorizedRoles: [ String ]
}));function roleCheck(jwt_, service) { var intersection = _.intersection(jwt_.roles, service.authorizedRoles); return intersection.length === service.authorizedRoles.length;
}