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README
¶
pgstore
Package pgstore is a PostgreSQL-based storage engine for the SCS session package.
Usage
Installation
Either:
$ go get github.com/alexedwards/scs/engine/pgstore
Or (recommended) use use gvt to vendor the engine/pgstore and session sub-packages:
$ gvt fetch github.com/alexedwards/scs/engine/pgstore
$ gvt fetch github.com/alexedwards/scs/session
Setup
You should have a working PostgreSQL database containing a sessions table with the definition:
CREATE TABLE sessions (
token TEXT PRIMARY KEY,
data BYTEA NOT NULL,
expiry TIMESTAMPTZ NOT NULL
);
CREATE INDEX sessions_expiry_idx ON sessions (expiry);
Example
package main
import (
"database/sql"
"io"
"log"
"net/http"
"time"
"github.com/alexedwards/scs/engine/pgstore"
"github.com/alexedwards/scs/session"
)
func main() {
// Establish a database/sql pool
db, err := sql.Open("postgres", "postgres://user:pass@localhost/db")
if err != nil {
log.Fatal(err)
}
defer db.Close()
// Create a new PGStore instance using the existing database/sql pool,
// with a cleanup interval of 5 minutes.
engine := pgstore.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 pgstore 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 PGstore instance:
// Run a cleanup every 30 minutes.
pgstore.New(db, 30*time.Minute)
// Setting the cleanup interval to zero prevents the cleanup from being run.
pgstore.New(db, 0)
Terminating the cleanup goroutine
It's rare that the cleanup goroutine for a PGStore 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 PGStore 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 PGStore 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("postgres", "postgres://user:pass@localhost/db")
if err != nil {
t.Fatal(err)
}
defer db.Close()
engine := New(db, time.Second)
defer engine.StopCleanup()
// Run test...
}
Notes
The pgstore package is underpinned by the excellent pq driver.
Full godoc documentation: https://godoc.org/github.com/alexedwards/scs/engine/pgstore.
Documentation
¶
Overview ¶
Package pgstore is a PostgreSQL-based storage engine for the SCS session package.
A working PostgreSQL database is required, containing a sessions table with the definition:
CREATE TABLE sessions ( token TEXT PRIMARY KEY, data BYTEA NOT NULL, expiry TIMESTAMPTZ NOT NULL ); CREATE INDEX sessions_expiry_idx ON sessions (expiry);
The pgstore 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("postgres", "postgres://user:pass@localhost/db")
if err != nil {
log.Fatal(err)
}
defer db.Close()
// Create a new PGStore instance using the existing database/sql pool,
// with a cleanup interval of 5 minutes.
engine := pgstore.New(db, 5*time.Minute)
sessionManager := session.Manage(engine)
http.ListenAndServe(":4000", sessionManager(http.DefaultServeMux))
}
The pgstore package is underpinned by the pq driver (https://github.com/lib/pq).
Index ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type PGStore ¶
PGStore represents the currently configured session storage engine.
func New ¶
New returns a new PGStore 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 (*PGStore) Delete ¶
Delete removes a session token and corresponding data from the PGStore instance.
func (*PGStore) Find ¶
Find returns the data for a given session token from the PGStore instance. If the session token is not found or is expired, the returned exists flag will be set to false.
func (*PGStore) Save ¶
Save adds a session token and data to the PGStore instance with the given expiry time. If the session token already exists then the data and expiry time are updated.
func (*PGStore) StopCleanup ¶
func (p *PGStore) StopCleanup()
StopCleanup terminates the background cleanup goroutine for the PGStore instance. It's rare to terminate this; generally PGStore 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 PGStore is transient. An example is creating a new PGStore instance in a test function. In this scenario, the cleanup goroutine (which will run forever) will prevent the PGStore 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("postgres", "postgres://user:pass@localhost/db")
if err != nil {
t.Fatal(err)
}
defer db.Close()
engine := pgstore.New(db, time.Second)
defer engine.StopCleanup()
// Run test...
}
Source Files