{"id":25,"date":"2016-03-17T10:50:58","date_gmt":"2016-03-17T10:50:58","guid":{"rendered":"http:\/\/www.librarypi.com\/?page_id=25"},"modified":"2016-04-01T01:05:37","modified_gmt":"2016-04-01T01:05:37","slug":"lp-stage-3","status":"publish","type":"page","link":"https:\/\/www.librarypi.com\/index.php\/lp-stage-3\/","title":{"rendered":"LP Stage 3"},"content":{"rendered":"

In stage 3 we are going to add some very basic authentication and registration.\u00a0 Basically, the site will support only one user, an administrator.\u00a0 Only that user will be able to add or delete books.<\/p>\n

Note that you can download a zip file of a Raspberry Pi disk image backup of Stage\u00a03 here ( NOTE: you will need to run sudo raspi-config<\/strong> to expand file space<\/em>):
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Library Pi Stage 3 Image<\/a><\/h3>\n
<\/i> 1 file(s) <\/i> 528 MB<\/div>\n <\/div>\n
\n Download<\/a>\n <\/div>\n <\/div>\n <\/div>\n<\/div>\n\n<\/div><\/p>\n

Or, you can also just download the Zip file with the Stage\u00a03 PHP files here (you still need to create the database, and setup lp_dbconf.php):
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PHP Files for Stage 3<\/a><\/h3>\n
<\/i> 1 file(s) <\/i> 313.96 KB<\/div>\n <\/div>\n
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SQL script for stage 3
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SQL Stage 3<\/a><\/h3>\n
<\/i> 1 file(s) <\/i> 1.21 KB<\/div>\n <\/div>\n
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Datamodel<\/h3>\n

We’re going to need some new tables in our datamodel: lp_user and lp_book_del.\u00a0 lp_user will contain a simple ID, login\/email, and password for user authentication, and lp_book_del will serve as a ‘recycle bin’ for deleted books so that we can delete them when it’s convenient.<\/p>\n

NOTE: The password is stored un-encrypted, which is a bad practice.\u00a0 I am leaving it this way for simplicity of demonstration.\u00a0 The password should use some salt with an MD5 hash so that if anyone steals or compromises the database their passwords aren’t exposed.\u00a0 I am also not enforcing any sort of minimal requirements for weak password.<\/em><\/p>\n

create table if not exists lp_user(\r\n\u00a0 id integer\u00a0 NOT NULL AUTO_INCREMENT,\r\n\u00a0 email varchar(254),\r\n\u00a0 password varchar( 32 ),\r\n\u00a0 connection_key varchar( 32 ),\r\n\u00a0 PRIMARY KEY PK_lp_used (id)\r\n);<\/pre>\n
create table if not exists lp_book_del (\r\n\u00a0 id integer,\r\n\u00a0 ukey varchar(32),\r\n\u00a0 PRIMARY KEY PK_lp_book_del (id)\r\n);<\/pre>\n
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Authentication<\/h3>\n
We are going to add a new lp_user<\/em> table to hold our login information.\u00a0 Since our LP->HTMLPageTop function is called at the top of every site page, we are going to add all the steps for authentication, which include Registration, Login, and Logout.\u00a0 HTMLPageTop will call 2 new functions to support this interaction: UserProcess() and UserHTML().<\/p>\n