Database Reference
In-Depth Information
To search for users to follow, the
UserController
uses the
Searchbyusername
method, which calls the
searchNotFollowing
in
UserService
. The first part of the
WHERE
clause in
searchNotFollowing
returns users whose
username matches on a wildcard String value (Listing 7-26). The second part of the
WHERE
clause in
searchNotFollowing
checks to make sure the users in the MATCH clause are not already being followed by the current user.
Listing 7-26.
searchNotFollowing
Method in the
UserService
// UserService
public List<User> searchNotFollowing(String currentusername, String username)
{
username = username.ToLower() + ".*";
List<User> following = _graphClient.Cypher
.Match(" (n:User), (user { username:{c}}) ")
.WithParam("c", currentusername.ToLower())
.Where(" (n.username =~ {u} AND n <> user) ")
.AndWhere("(NOT (user)-[:FOLLOWS]->(n)) ")
.WithParam("u", username)
.Return(n => n.As<User>())
.OrderBy("n.username")
.Results.ToList<User>();
return following;
}
The
searchByUsername
in
{PROJECTROOT}/Content//js/graphstory.js
uses an AJAX request and formats the
response in
renderSearchByUsername
. If the list contains users, it will be displayed in the center of the page under the
search form, as shown in Figure
7-5
. Otherwise, the response will display “No Users Found”.
Once the search returns results, the next action would be to click on the “Add as Friend” link, which will call the
addfriend
method in
graphstory.js
. This will perform an AJAX request to the
follow
method in the
UserController
and call
follow
in
UserService
. The
follow
method in
UserService
, shown in Listing 7-27, will create the
relationship between the two users by first finding each entity via the
MATCH
clause and then use the
CreateUnique
clause to create the directed
FOLLOWS
relationship. Once the operation is completed, the next part of the query then
runs a
MATCH
on the users being followed to return the full list of followers ordered by the username.
Listing 7-27.
The
follow
Method
// UserService
// follows a user and also returns the list of users being followed
public List<User> follow(String currentusername, String username)
{
List<User> following = _graphClient.Cypher
.Match(" (user1:User {username:{cu}} ), (user2:User {username:{u}} ) ")
.WithParams(new { cu = currentusername.ToLower(), u = username.ToLower() })
.CreateUnique("user1-[:FOLLOWS]->user2")
.With(" user1 ")
.Match(" (user1)-[f:FOLLOWS]->(users) ")
