Import by require the folder database.

For example,

var database = require('../database');

var return_code = database.sign_in(id, pass);

The provided APIs:

• sign_in(id, pass), return:
  • 0 if success
  • -2 if user ID already exists
  • -3 if internal error
• sign_up(id, pass), return:
  • 0 if success
  • -1 if password incorrect
  • -2 if user ID does not exist
  • -3 if internal error
• get_msgsrcs(userid), get the list of message sources, return:
  • An array of objects. The structure of object is {SrcID, SrcDesc, URL, flag} (name of properties), among which SrcID is the ID of message source, SrcDesc is its description, URL is its URL link, and flag shows if the user has subscribed it. For example, if you would like know the message source ID of the second entry,

var result = get_msgsrcs(`MyUserID`);

console.log(result[1].SrcID);

• add_msgsrc(userid, srcid), add message source for user, return:
  • 0: if success
  • -3: if internal error
• rm_msgsrc(userid, srcid), remove message source for user, return:
  • 0: if success
  • -3: if internal error

Note:

1. All the passwords needed when you invoke the APIs are in PLAINTEXT. The passwords will be hashed and stored in database, which is encapsulated and intransparent to callers.
2. The structure of database tables:

• UserPass

CREATE TABLE UserPass ( UserID varchar(32), Password char(60), PRIMARY KEY(UserID));

• MsgSrc

CREATE TABLE MsgSrc (SrcID varchar(32), SrcDesc varchar(256), URL varchar(256), PRIMARY KEY(SrcID));

• UserSrc

CREATE TABLE UserSrc (UserID varchar(32), SrcID varchar(32), PRIMARY KEY(UserID, SrcID), FOREIGN KEY (UserID) REFERENCES UserPass(UserID), FOREIGN KEY (SrcID) REFERENCES MsgSrc(SrcID));

• Msg

CREATE TABLE Msg (MsgID int AUTO_INCREMENT, SrcID varchar(32) NOT NULL, Brief varchar(255), Detail mediumtext, PRIMARY KEY (MsgID), FOREIGN KEY (SrcID) REFERENCES MsgSrc(SrcID));