func newUser() string {
return "uid_" + x.UniqueString(3)
}
func main() {
rand.Seed(time.Now().UnixNano())
fmt.Println("Running...")
flag.Parse()
c = new(req.Context)
if *storeType == "leveldb" {
l := new(store.Leveldb)
l.SetBloomFilter(13)
c.Store = l
c.Store.Init("/tmp/ldb_" + x.UniqueString(10))
} else if *storeType == "cass" {
cluster := gocql.NewCluster("192.168.59.103")
cluster.Keyspace = "crudtest"
cluster.Consistency = gocql.Quorum
cass := new(store.Cassandra)
if session, err := cluster.CreateSession(); err != nil {
panic(err)
} else {
cass.SetSession(session)
}
c.Store = cass
c.Store.Init("instructions")
} else if *storeType == "mysql" {
db, err := sql.Open("mysql", "root@tcp(127.0.0.1:3306)/test")
if err != nil {
panic(err)
}
if err = db.Ping(); err != nil {
panic(err)
}
log.Info("Connection to mysql successful")
sqldb := new(store.Sql)
sqldb.SetDb(db)
c.Store = sqldb
c.Store.Init("instructions")
} else if *storeType == "datastore" {
c.TablePrefix = "Test-"
c.Store = new(store.Datastore)
c.Store.Init("gce-project-id")
} else {
panic("Invalid store")
}
var err error
uid := newUser()
// Let's get started. User 'uid' creates a new Post.
// This Post shares a url, adds some text and some tags.
tags := [3]string{"search", "cat", "videos"}
err = api.Get("User", uid).SetSource(uid).AddChild("Post").
Set("url", "www.google.com").Set("body", "You can search for cat videos here").
Set("tags", tags).Execute(c)
if err != nil {
log.Fatalf("Error: %v", err)
}
fmt.Print("Stored Post")
// Now let's add a comment and two likes to our new post.
// One user would add a comment and one like. Another user would
// just like the post.
//
// It's best to have the same 'source' for one set of operations.
// In REST APIs, this is how things would always be. Each REST call
// is from one user (and never two different users).
// This way the creation of like "entity", and the properties
// of that new like entity have the same source.
//
// So, here's Step 1: A new user would add a comment, and like the post.
user := printAndGetUser(uid)
post := user.Post[0]
p := api.Get("Post", post.Id).SetSource(newUser())
p.AddChild("Like").Set("thumb", 1)
p.AddChild("Comment").Set("body",
fmt.Sprintf("Comment %s on the post", x.UniqueString(2)))
err = p.Execute(c)
if err != nil {
log.Fatalf("Error: %v", err)
}
// Step 2: Another user would now like the post.
p = api.Get("Post", post.Id).SetSource(newUser())
p.AddChild("Like").Set("thumb", 1)
err = p.Execute(c)
if err != nil {
log.Fatalf("Error: %v", err)
}
fmt.Print("Added 1 Comment and 2 Like on Post")
user = printAndGetUser(uid)
post = user.Post[0]
if len(post.Comment) == 0 {
log.Fatalf("No comment found: %+v", post)
}
comment := post.Comment[0]
// Now another user likes and replies to the comment that was added above.
// So, it's a comment within a comment.
p = api.Get("Comment", comment.Id).SetSource(newUser())
p.AddChild("Like").Set("thumb", 1)
p.AddChild("Comment").Set("body",
fmt.Sprintf("Comment %s on comment", x.UniqueString(2)))
err = p.Execute(c)
if err != nil {
log.Fatalf("Error: %v", err)
}
fmt.Print("Added Comment on Comment")
user = printAndGetUser(uid)
post = user.Post[0]
if len(post.Comment) == 0 {
log.Fatalf("No comment found: %+v", post)
}
comment = post.Comment[0]
if len(comment.Like) == 0 {
log.Fatalf("No like found: %+v", comment)
}
like := comment.Like[0]
// So far we have this structure:
// User
// L Post
// L 2 * Like
// L Comment
// L Comment
// L Like
// This is what most social platforms do. But, let's go
// one level further, and also comment on the Likes on Comment.
// User
// L Post
// L 2 * Like
// L Comment
// L Comment
// L Like
// L Comment
// Another user Comments on the Like on Comment on Post.
p = api.Get("Like", like.Id).SetSource(newUser()).
AddChild("Comment").Set("body",
fmt.Sprintf("Comment %s on Like", x.UniqueString(2)))
err = p.Execute(c)
if err != nil {
log.Fatalf("Error: %v", err)
}
fmt.Print("Added Comment on Like")
user = printAndGetUser(uid)
post = user.Post[0]
if len(post.Comment) == 0 {
log.Fatalf("No comment found: %+v", post)
}
comment = post.Comment[0]
p = api.Get("Comment", comment.Id).SetSource(newUser()).Set("censored", true)
err = p.Execute(c)
if err != nil {
log.Fatalf("Error: %v", err)
}
q := api.NewQuery("Comment", comment.Id).UptoDepth(0)
result, err := q.Run(c)
if err != nil {
log.Fatalf("Error: %v", err)
}
js, err := result.ToJson()
if err != nil {
log.Fatalf("Error: %v", err)
}
fmt.Printf("\n%s\n%s\n%s\n", sep, string(js), sep)
user = printAndGetUser(uid)
post = user.Post[0]
if len(post.Like) == 0 {
log.Fatalf("No like found: %+v", post)
}
like = post.Like[0]
p = api.Get("Like", like.Id).SetSource(newUser()).MarkDeleted()
err = p.Execute(c)
if err != nil {
log.Fatalf("Error: %v", err)
}
q = api.NewQuery("User", uid).Collect("Post")
q.Collect("Like").UptoDepth(10)
q.Collect("Comment").UptoDepth(10).FilterOut("censored")
result, err = q.Run(c)
if err != nil {
log.Fatalf("Error: %v", err)
}
js, err = result.ToJson()
if err != nil {
log.Fatalf("Error: %v", err)
}
fmt.Printf("\n%s\n%s\n%s\n", sep, string(js), sep)
// By now we have a fairly complex Post structure. CRUD for
// which would have been a lot of work to put together using
// typical SQL / NoSQL tables.
}
func (n *Node) doExecute(c *req.Context, its *[]*x.Instruction) error {
for pred, val := range n.edges {
if len(n.source) == 0 {
return errors.New(fmt.Sprintf(
"No source specified for id: %v kind: %v", n.id, n.kind))
}
i := new(x.Instruction)
i.SubjectId = n.id
i.SubjectType = n.kind
i.Predicate = pred
if b, err := json.Marshal(val); err != nil {
return err
} else {
i.Object = b
}
i.Source = n.source
i.NanoTs = n.Timestamp
log.WithField("instruction", i).Debug("Pushing to list")
*its = append(*its, i)
}
if len(n.children) == 0 {
return nil
}
if len(n.source) == 0 {
return errors.New(fmt.Sprintf(
"No source specified for id: %v kind: %v", n.id, n.kind))
}
// Children can only be added, not deleted via API. But they can be stopped
// from being retrieved.
// Scenario: How do I stop childA from being retrieved?
// Answer:
// Modify child by adding a 'deleted' edge
// Get(ChildKind, ChildId).Set("deleted", true).Execute(c)
//
// Then for retrieval from parent:
// NewQuery(ParentKind, ParentId).Collect(ChildKind).FilterOut("deleted")
// This would remove all children with a 'deleted' edge.
for _, child := range n.children {
if len(child.id) > 0 {
log.WithField("child_id", child.id).Fatal(
"Child id should be empty for all current use cases")
return errors.New("Non empty child id")
}
for idx := 0; ; idx++ {
child.id = x.UniqueString(5)
log.WithField("id", child.id).Debug("Checking availability of new id")
if isnew := c.Store.IsNew(c.TablePrefix, child.id); isnew {
log.WithField("id", child.id).Debug("New id available")
break
}
if idx >= 30 {
return errors.New("Unable to find new id")
}
}
// Create edge from parent to child
i := new(x.Instruction)
i.SubjectId = n.id
i.SubjectType = n.kind
i.Predicate = child.kind
i.ObjectId = child.id
i.Source = n.source
i.NanoTs = n.Timestamp
log.WithField("instruction", i).Debug("Pushing to list")
*its = append(*its, i)
if err := child.doExecute(c, its); err != nil {
return err
}
}
return nil
}
