connect-datacache
v1.1.0
Published
Express session connector for IBM DataCache
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connect-datacache
NodeJS express-session storage for IBM Bluemix Data Cache service.
Setup
npm install connect-datacache
Using the DataCache storage connector:
var session = require('express-session');
var DataCacheStore = require('connect-datacache')(session);
app.use(session({
store: new DataCacheStore(options),
secret: 'keyboard cat'
}));
Standard usage for Bluemix environment/dev environment - with fallback on MemoryStore:
dcStore = null;
try {
// by default is looking into bluemix cfenv services
dcStore = new DataCacheStore();
} catch (err) {
// log fallback on memory store for no DataCache service linked to app
}
app.use(session({
store: dcStore,
secret: 'keyboard cat'
}));
Storage Options
Bellow is an example with the full list of parameters - default values for optional ones:
var store = new DataCacheStore({
// required parameters when no custom client provided or no ENV credentials are set
restResource: 'http://dcsdomain.bluemix.net/resources/datacaches/{gridName}',
restResourceSecure: 'https://dcsdomain.bluemix.net/resources/datacaches/{gridName}',
gridName: '{gridName}',
username: '{username}',
password: '{password}',
// optional parameters - default values
mapName: '{gridName}',
eviction: 'LUT',
locking: 'optimistic',
contentType: 'application/json',
secure: true,
ttl: 3600,
prefix: 'sess:',
cfServiceName: null,
client: null
}
);
Bluemix environment
The datacache client is looking first for DataCache service cfenv values. For the Bluemix NodeJS app with a DataCache service associated the required parameters are read from ENV variables (credentials):
Environment Variables > VCAP_SERVICES
{
"system_env_json": {
"VCAP_SERVICES": {
"DataCache-dedicated": [
{
"credentials": {
"catalogEndPoint": "...",
"restResource": "http://ip-numeric/resources/datacaches/SYS_GENERATED_GRIDNAME",
"restResourceSecure": "https://sdomain.bluemix.net/resources/datacaches/SYS_GENERATED_GRIDNAME",
"gridName": "SYS_GENERATED_GRIDNAME",
"username": "SYS_GENERATED_USERNAME",
"password": "SYS_GENERATED_PASSWORD"
},
"name": "datacache-service-name",
"tags": []
}
]
}
},
}
restResources/restResourceSecure
defaults: VCAP_SERVICES credentials values
Depending on the "secure" value, one of them is required if not found in ENV variables by cfenv.
mapName
For a Bluemix application it is required to have the same value as for "gridName". A resource is identified with a complete URI as:
http://secure.domain/resources/datacaches/SYS_GENERATED_GRIDNAME/MAP_NAME.EVICTION.LOCK/SESSION_KEY
ex: https://ecaas3.w3ibm.bluemix.net/resources/datacaches/Ae7hjz7tQjuxF44ncLAvuQGH/Ae7hjz7tQjuxF44ncLAvuQGH.LUT.O/sess:t7OQGXZ3x8TNp269-lf-wsdnUBx5OcU6
For non-Bluemix environments it can be customized as a namespace for data.
eviction
- 'LUT' - default - expires based on the Last Update Time
- 'NONE' - data is stored indefinitly (until si programaticaly deleted)
- 'LAT' - expires based on Last Access Time
locking
- 'optimistic' - default
- 'pessimistic'
contentType
- 'application/json' - default - turns on the JSON encoder/decoder for session data
- other - saves session data as plain text
secure
- true - default - uses 'restResourceSecure' as store entrypoint
- false - uses 'restResource' as store entrypoint
ttl
- session/storage time to live - overrides the cookie maxAge value if present
prefix
- custom prefix to be appended for all session keys
cfServiceName
- allows using multiple Data Cache services for same application - loads credentials from ENV using service name;
var store = new DataCacheStore({'cfenvServiceName': 'datacache-service-name'});
client
- offers option to pass an instance of DataCacheClient or inteface matching object -> turns optional all the required parameters/credentials
Contributing
- PR code needs to pass the lint check and unit test
npm test
- PR code should be covered by UT
npm run coverage
Resources
- http://www.ibm.com/support/knowledgecenter/SSTVLU_8.6.0/com.ibm.websphere.extremescale.doc/tdevrest.html
- https://console.ng.bluemix.net/docs/services/DataCache/index.html#datac001
Attributions
- The connect-datacache code is based on implementation from other express-session storages as: connect-redis