/
data.go
112 lines (98 loc) · 2.7 KB
/
data.go
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package main
import (
"fmt"
"golang.org/x/net/context"
"google.golang.org/appengine"
"google.golang.org/appengine/datastore"
"google.golang.org/appengine/user"
"net/http"
"time"
)
type Profile struct {
Email string
Username string
}
type Tweet struct {
Message string
Time time.Time
Username string
}
// get profile by username
func getProfileByUsername(req *http.Request, username string) (*Profile, error) {
ctx := appengine.NewContext(req)
q := datastore.NewQuery("Profile").Filter("Username =", username).Limit(1)
var profiles []Profile
_, err := q.GetAll(ctx, &profiles)
if err != nil {
return nil, err
}
if len(profiles) == 0 {
return nil, fmt.Errorf("profile not found")
}
return &profiles[0], nil
}
// get profile by email
func getProfileByEmail(ctx context.Context, email string) (*Profile, error) {
key := datastore.NewKey(ctx, "Profile", email, 0, nil)
var profile Profile
err := datastore.Get(ctx, key, &profile)
if err != nil {
return nil, err
}
return &profile, nil
}
// get profile
func getProfile(ctx context.Context) (*Profile, error) {
u := user.Current(ctx)
return getProfileByEmail(ctx, u.Email)
}
// create profile
func createProfile(req *http.Request, profile *Profile) error {
ctx := appengine.NewContext(req)
key := datastore.NewKey(ctx, "Profile", profile.Email, 0, nil)
_, err := datastore.Put(ctx, key, profile)
return err
// you can use memcache also to improve your consistency
}
// for eventual consistency thing
// assumption: user will show up in 10 seconds on datastore
func waitForProfile(req *http.Request, username string) error {
deadline := time.Now().Add(time.Second * 10)
for time.Now().Before(deadline) {
_, err := getProfileByUsername(req, username)
if err == nil {
return nil
}
time.Sleep(time.Second * 1)
}
return nil
}
//// insert tweet
func putTweet(ctx context.Context, tweet *Tweet, email string) error {
userKey := datastore.NewKey(ctx, "Profile", email, 0, nil)
tweetKey := datastore.NewIncompleteKey(ctx, "Tweet", userKey)
_, err := datastore.Put(ctx, tweetKey, tweet)
if err != nil {
return err
}
return nil
}
// get user tweets
func userTweets(ctx context.Context, email string) ([]Tweet, error) {
var tweets []Tweet
userKey := datastore.NewKey(ctx, "Profile", email, 0, nil)
q := datastore.NewQuery("Tweet").Ancestor(userKey).Order("-Time").Limit(20)
_, err := q.GetAll(ctx, &tweets)
return tweets, err
}
// get recent tweets
func recentTweets(ctx context.Context) ([]Tweet, error) {
var tweets []Tweet
q := datastore.NewQuery("Tweet").Order("-Time").Limit(20)
_, err := q.GetAll(ctx, &tweets)
return tweets, err
}
//// delete tweet
//func delTweet(ctx context.Context, username string) (*Profile, error) {
//
//}