README
¶
qlstore
Package qlstore is a ql storage engine for the SCS session package.
Usage
Installation
Either:
$ go get github.com/alexedwards/scs/engine/qlstore
Or (recommended) use use gvt to vendor the engine/qlstore and session sub-packages:
$ gvt fetch github.com/alexedwards/scs/engine/qlstore
$ gvt fetch github.com/alexedwards/scs/session
Setup
A working ql database is required, containing a sessions table with the definition:
CREATE TABLE sessions (
token string,
data blob,
expiry time
);
CREATE INDEX sessions_expiry_idx ON sessions (expiry);
Example
package main
import (
"database/sql"
"io"
"log"
"net/http"
"time"
"github.com/alexedwards/scs/engine/qlstore"
"github.com/alexedwards/scs/session"
)
func main() {
// Establish a database/sql pool
db, err := sql.Open("ql", "example.db")
if err != nil {
log.Fatal(err)
}
defer db.Close()
// Create a new qlstore instance using the existing database/sql pool,
// with a cleanup interval of 5 minutes.
engine := qlstore.New(db, 5*time.Minute)
sessionManager := session.Manage(engine)
http.HandleFunc("/put", putHandler)
http.HandleFunc("/get", getHandler)
http.ListenAndServe(":4000", sessionManager(http.DefaultServeMux))
}
func putHandler(w http.ResponseWriter, r *http.Request) {
err := session.PutString(r, "message", "Hello world!")
if err != nil {
http.Error(w, err.Error(), 500)
}
}
func getHandler(w http.ResponseWriter, r *http.Request) {
msg, err := session.GetString(r, "message")
if err != nil {
http.Error(w, err.Error(), 500)
}
io.WriteString(w, msg)
}
Cleaning up expired session data
The qlstore package provides a background 'cleanup' goroutine to delete expired session data. This stops the database table from holding on to invalid sessions indefinitely and growing unnecessarily large.
You can specify how frequently to run the cleanup when creating a new qlstore instance:
// Run a cleanup every 30 minutes.
qlstore.New(db, 30*time.Minute)
// Setting the cleanup interval to zero prevents the cleanup from being run.
qlstore.New(db, 0)
Terminating the cleanup goroutine
It's rare that the cleanup goroutine for a qlstore instance needs to be terminated. It is generally intended to be long-lived and run for the lifetime of your application.
However, there may be occasions when your use of a qlstore instance is transient. A common example would be using it in a short-lived test function. In this scenario, the cleanup goroutine (which will run forever) will prevent the qlstore object from being garbage collected even after the test function has finished. You can prevent this by manually calling StopCleanup().
For example:
func TestExample(t *testing.T) {
db, err := sql.Open("ql", "test.db")
if err != nil {
t.Fatal(err)
}
defer db.Close()
engine := New(db, time.Second)
defer engine.StopCleanup()
// Run test...
}
Notes
The qlstore package is underpinned by the excellent ql driver.
Full godoc documentation: https://godoc.org/github.com/alexedwards/scs/engine/qlstore.
Documentation
¶
Overview ¶
Package qlstore is a ql-based storage engine for the SCS session package.
A working ql database is required, containing a sessions table with the definition:
CREATE TABLE sessions ( token string, data blob, expiry time ) CREATE INDEX sessions_expiry_idx ON sessions (expiry);
The qlstore package provides a background 'cleanup' goroutine to delete expired session data. This stops the database table from holding on to invalid sessions indefinitely and growing unnecessarily large.
Usage:
func main() {
// Establish a database/sql pool
db, err := sql.Open("ql", "example.db")
if err != nil {
log.Fatal(err)
}
defer db.Close()
// Create a new QLStore instance using the existing database/sql pool,
// with a cleanup interval of 5 minutes.
engine := qlstore.New(db, 5*time.Minute)
sessionManager := session.Manage(engine)
http.ListenAndServe(":4000", sessionManager(http.DefaultServeMux))
}
The qlstore package is underpinned by the pq driver (github.com/cznic/ql/driver).
Index ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
Types ¶
type QLStore ¶
QLStore represents the currently configured session storage engine.
func New ¶
New returns a new QLStore instance.
The cleanupInterval parameter controls how frequently expired session data is removed by the background cleanup goroutine. Setting it to 0 prevents the cleanup goroutine from running (i.e. expired sessions will not be removed).
func (*QLStore) Delete ¶
Delete removes a session token and corresponding data from the QLStore instance.
func (*QLStore) Find ¶
Find returns the data for a given session token from the QLStore instance. If the session token is not found or is expired, the returned exists flag will be set to false.
func (*QLStore) Save ¶
Save adds a session token and data to the QLStore instance with the given expiry time. If the session token already exists then the data and expiry time are updated.
func (*QLStore) StopCleanup ¶
func (q *QLStore) StopCleanup()
StopCleanup terminates the background cleanup goroutine for the QLStore instance. It's rare to terminate this; generally QLStore instances and their cleanup goroutines are intended to be long-lived and run for the lifetime of your application.
There may be occasions though when your use of the QLStore is transient. An example is creating a new QLStore instance in a test function. In this scenario, the cleanup goroutine (which will run forever) will prevent the QLStore object from being garbage collected even after the test function has finished. You can prevent this by manually calling StopCleanup.
Example:
func TestExample(t *testing.T) {
db, err := sql.Open("ql", "test.db")
if err != nil {
t.Fatal(err)
}
defer db.Close()
engine := pgstore.New(db, time.Second)
defer engine.StopCleanup()
// Run test...
}
Source Files