cicyle dependecies

[yuu2lee4]

when i use koa-generic-session-mongo with koa-session-minimal in koa2, it tell me cicyle dependecies this is my app.js: and i just get a user from mongodb , and set it to session.user: my node version is 7.2.1,and i use it with --harmony to handle async function.

[lzztt]

Hi yuu2lee4,

Nothing indicates that this is a session middleware issue. I created a simple test example with mongo store and tested with node/v7.2.1 with the --harmony option. The session works fine. Can you test with example/07_mongodb_store.js?

Here is the shell output of my test:

# clone repo
ikki@dev:/tmp$ git clone https://github.com/longztian/koa-session-minimal.git
... ...

ikki@dev:/tmp$ cd koa-session-minimal/

# install dependencies
ikki@dev:/tmp/koa-session-minimal$ npm install
... ...

# node version
ikki@dev:/tmp/koa-session-minimal$ node -v
v7.2.1

# build dist and run tests
ikki@dev:/tmp/koa-session-minimal$ make 

# mongodb record before running example
ikki@dev:/tmp/koa-session-minimal$ echo 'db.sessions.find()' | mongo
MongoDB shell version: 2.6.12
connecting to: test
{ "_id" : ObjectId("584c639b40a525d58ea26ae9"), "count" : 12, "sid" : "koa:sess:eGyFRjiJ0TwJykty_0-RNJG4sR9itXSg", "ttl" : ISODate("2016-12-11T20:56:05.598Z") }
bye

# start example server and visit localhost:3000 from a browser
ikki@dev:/tmp/koa-session-minimal$ node --harmony example/07_mongodb_store.js 
^C

# mongodb record after running example
ikki@dev:/tmp/koa-session-minimal$ echo 'db.sessions.find()' | mongo
MongoDB shell version: 2.6.12
connecting to: test
{ "_id" : ObjectId("584c639b40a525d58ea26ae9"), "count" : 15, "sid" : "koa:sess:eGyFRjiJ0TwJykty_0-RNJG4sR9itXSg", "ttl" : ISODate("2016-12-11T20:58:06.751Z") }
bye

[lzztt]

Hi yuu2lee4,

I just got a hint from this ticket. The error message showed that bson library could not serialize the data (before putting it into MongoDB session collection). The user is a MongoDB document which may be deeply bond to a MongoDB record in the database. Now since you were using mongo store as your session store, you were trying to save a document from the user collection into the session collection. I guess the mongo store uses bson to serialize data, then it hits a circular serialization when trying to serialize some internal data of your user object.

You can either use a different session store, or convert your user object to a plain javascript object (with any fields you want to keep) and save it to ctx.session.user. like below:

ctx.session.user = {
    id: user._id,
    name: user.name,
}

I prefer the second way. So that you know exactly what kind of data (after serialization) is saved to your session store. Let me know if this works for you.

[yuu2lee4]

many tks, the second way is worked