PHPHomeworkforWeek14·Chapter12·CookiesandSessions

Exercise1.Cookies.

Thetextbooktellsyouaboutcookiesbutdoesnotreallygiveyoumuchsamplecode.Thisisthesimplestpossiblesetofpagesthatwillletyoucommunicatebetweentwopagesusingacookie.

File1.Form.1. CreateafolderandcallitChapter12.Yourworkwillgointhisfolder.2. CreateanHTML/PHPfile.Saveitassetcookie.php.Thiswillbeanall-in-oneformthathas

theformhandlerwithintheform.Theformhandlerjustsetsacookie.3. Theformalsohasanoptiontologtheuserout,whichdeletesthecookie.Notethatboth

buttonshavethenameofsubmitbuttheyhavedifferentvalues.4. Putthiscodeinsetcookie.php:

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File2.Seethecookie.1. CreateanHTML/PHPfile.Saveitasgetcookie.php.2. Putthiscodeinthegetcookie.phpfile.Thiscodereadsthecookieanddisplaysitsvalue.

Exercise2.Sessions.

Thetextbookhassomesamplecodeforsessions.Ihadaproblemwiththeirsamplecode.Theauthenticationcodedoesnotwork.Anyway,thecodemaybealittleoverlycomplicated.Icreatedasystemthatperformsasimilarfunctionwithoutdoingtheencryption.Thisway,youcanseethesessioncodewithoutgettingittangledupwiththeencryptioncode.IreplacedtheHTTPauthenticationwithanHTMLformthatchecksitsvaluesagainstaMySQLdatabase.

Thetextbook’sauthenticationmechanism,whichusesHTTPauthentication,isnotusedverymuch.Oneproblemisthatonceloggedin,itisnotpossibletologbackoutandloginagainasanewuser.Soitisdifficulttotesttheauthenticationcodetomakesureitwon’tauthenticateabadusername/passwordcombination.

File1.Logincredentials.

1. Putyourlogin.phpfilefromlastThursdaynight(orseetextbookpage234)inaplacewhereyoucanincludeit,eitherintherootlevelofyourwebsite(htdocs,www,orpublic_html)orintheChapter12folder.

File2.Formforaddinganewuser.

1. CreateanHTMLfile.Callitnewuser.html.ItwillhaveonlyHTMLcode.2. Theformwilllooklikethis:

3. Theformcodewilllooklikethis:

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File3.Formhandlerforaddinganewuser.

1. CreateaPHPfile.Saveitasnewuser.php.Putthefollowingcodeinthefile:

File4.Loginaregistereduser.1. CreateanewPHPfile.Saveitassession.php.(Thefilenamelogin.phpisalreadyinuse.)

File5.Seewhoisloggedin.

1. CreateanewPHPfile.Saveitascontinue.php.

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File6.Logoutanddeletethesession.

1. CreateanewPHPfile.Saveitaslogout.php.

Exercise3.Useacookieonavisitcounter.

1. Objective:addavisitorcounterinaMySQLdatabase.Updatethevisitorcounteronlyfornewvisitorsbysettingacookiethefirsttimetheyvisit.Createaninterfacefordeletingthecookiesowecantestthecookiemechanism.DisplaythevisitorcountinthefooterofyourProject.

2. CreateaMySQLtableforstoringthevisitorcount.CREATE TABLE counter (id INT NOT NULL PRIMARY KEY, counter INT); INSERT INTO counter VALUES (1, 0);

3. InyourProject,addthiscodeinheaders.phptoupdatethevisitorcounterwheneversomeonevisitsanypageonyoursite:<?php require_once('login.php'); $conn = new mysqli($hn, $un, $pw, $db); if ($conn->connect_error) die($conn->connect_error); if (empty ($_COOKIE['visited'])) { $query = "UPDATE counter SET counter=counter+1 WHERE id=1"; $result = $conn->query($query); $query = "SELECT counter FROM counter WHERE id=1"; $result = $conn->query($query); $result->data_seek(0); $row = $result->fetch_array(MYSQLI_ASSOC); $visitors = $row['counter']; setcookie ("visited", $visitors, time()+(60*60*24)); } else { $visitors = $_COOKIE['visited']; } ?>

4. NotethattheabovecookiecodemustappearbeforeanyHTMLcodethatmightbeprintedwithinyourPHPfile.TheremustnotbeevenasinglespacebeforetheaboveblockofPHPcode.

5. Inyourproject’sfooter.phpfile,addthisPHPcode:<?php echo "<p>Total visitors to this site: $visitors </p>\n"; ?>

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6. CreateanewfileforyourProjectcalledstate.php(ifyouhaven’tdonesoalready).

7. Linkthestate.phpfiletothebuttonsthatsayStateInformation.

8. Inthestate.phpfile,givesomeinformationaboutstatemechanisms,andprovidealinkorbuttonwheretheusercandeletethecookie.Youcanseeanexampleofthiswebpagehere:

http://php.missioncollege.edu/~markb/project/state.php

9. Thelinkorbuttonforremovingthecookieshouldlinktoafilethatyoumightcall

removecookie.phpordeletecookie.php.Itshouldhavecodelikethis,whichremovesthecookieatthetopofthefile,thenincludesalltheotherheadersandnavigationthatareapartofyourtemplate.Providealinkbacktothestate.phppage.

<?php setcookie('visited', '', time() - 1000000, "/"); ?> <?php include "header.php"; ?> <div id='content'> <h1>PHP Class Project</h1> <div id='textnav'> <?php include "textnav.php"; ?> </div> <div id='buttonnav'> <?php include "buttonnav.php"; ?> </div> <div id='main'> <h2>State Information</h2> <p>Cookie deleted</p> <a href='state.php'>Back</a> </div> <!-- main --> </div> <!-- content --> <?php include "footer.php"; ?>

10. Notethatthecodeforremovingacookieinvolvessettingittoanemptystringwithanexpirationdate

inthepast.Thisisjustsamplecodethatfitsmytemplate.Yourtemplatemaybedifferent. Exercise4.

LinkallthesefilestoyourhomepagesoIcanlookatthemquickly.