1. PHP+SQL 3. Files, directories, images TWIG File-based "database"
File-based guestbook
Exercises
OE NIK 2013

2. PHP+SQL 3. Files, directories, images TWIG File-based "database"
File-based guestbook
Exercises
OE NIK 2013

3. Basic principles
File paths: document_root (<a href=‘/path/to/file’>) vs php disk root ($path=‘/path/to/file’)
In symfony, the document_root is the WEB directory, all PHP file access is relative to that directory
File handle (file variable), file modes
Concurrent file access, race condition bug
Permissions (www-data/IUSR vs ftp-user)
EOL byte(s)?
EOF byte?
OE NIK 2013

4. Functions
file_exists($path), fopen($path, $mode), fclose($fp), feof($fp)
fwrite($fp, $s)=fputs($fp, $s)=binary-safe write
fgetc($fp), fgets($fp), fread($fp, $len), rewind($fp)
file($path)
fpassthru($fp), readfile($path)
realpath($path), basename($path), unlink($path), pathinfo($path), filesize($path)
$fname="path/to/file.txt";
$cont=file_get_contents($fname);
$cont.="hellobello";
file_put_contents($fname, $cont);
OE NIK 2013

5. Usage of files (one row contents)
<?php $fp=fopen("welcome.txt","wb"); //file handle fwrite($fp, "Hello world\n"); //same: fputs() fclose($fp); //close file $fp=fopen("welcome.txt","r"); $str=fgets($fp); //fread: not the same! echo $str; fclose($fp); ?>
OE NIK 2013

6. File modes Modes Description r
Read only. Starts at the beginning of the file r+
Read/Write. Starts at the beginning of the file w
Write only. Opens and clears the contents of file; or creates a new file if it doesn't exist w+
Read/Write. Opens and clears the contents of file; or creates a new file if it doesn't exist a
Append. Opens and writes to the end of the file or creates a new file if it doesn't exist a+
Read/Append. Preserves file content by writing to the end of the file x
Write only. Creates a new file. Returns FALSE and an error if file already exists x+
Read/Write. Creates a new file. Returns FALSE and an error if file already exists
OE NIK 2013

7. Perfect use
<?php $handle "r"); if ($handle) { while (($buffer = fgets($handle, 4096)) !== false) { echo $buffer; } if (!feof($handle)) { echo "Error: unexpected fgets() fail\n"; fclose($handle); ?>
OE NIK 2013

8. WRONG use
$file = fopen("welcome.txt", "r"); while(!feof($file)) { //infinite loop!!!!!! echo fgets($file)."<br />"; } fclose($file); Alternative solution: $file = fopen("welcome.txt", "r") or die("Unable to open file!");
OE NIK 2013

9. Directory Functions getcwd() , chdir()
opendir(), readdir(), closedir(), rewinddir()
scandir(), glob()
realpath()
OE NIK 2013

10. GD Functions image* , http://php.net/manual/en/book.image.php
$im=imagecreatefromjpeg($path) //png, gif, wbmp
imagesy($im), imagesx($im)
$index=imagecolorat($im, X, Y);
$rgb=imagecolorsforindex($im, $index);
$index=imagecolorallocate($im, R, G, B);
imagesetpixel($im, X, Y, $index);
OE NIK 2013

11. GD Example – pagetitle.php
OE NIK 2013

12. GD Example – getChannel.php
OE NIK 2013

13. PHP+SQL 3. Files, directories, images TWIG File-based "database"
File-based guestbook
Exercises
OE NIK 2013

14. TWIG Templating engine (Blade, smarty, native php)
{{ … }} = “says something” {{ }} = prints out the variable passed to the templating engine {{ user. }} = prints out the member of the user variable passed to the templating engine (intelligent member search!)
{% … %} = “does something” {% for … %}, {% if … %}, {% set … %}
{# … #} = “comments something”
OE NIK 2013

15. Variables Global Local
app.user [logged in user’s data]
app.request [request info]
app.session [session data]
app.environment [environment info]
app.debug [true/false]
Local
When displaying from the controller, an array of variables can be passed from the controller to the view
Variables can be arrays/object/scalars, member access is done with the . Operator (intelligent search)
Everything is converted to strings!
OE NIK 2013

16. Active elements
Filters can be applied to template variables, can be chained if necessary: {{ someDateTime|date(‘Y.m.d. H:i:s’) }} {{ |lower }} {{ |default(‘nothing’)|upper }}
Loops, functions:
OE NIK 2013

17. Links / references
<a href=‘{{ path(‘someRouteName’) }}’>LINK</a>
<a href='{{ path('article_show', {'id': article.id }) }}'>
{{ url(‘someRouteName’) }} = absolute url
<img src=“{{ asset('images/logo.png') }}" />
OE NIK 2013

18. Fast, secure and “the right way”
Fast: effective caching (PHP classes are generated an then cached in var/cache/*/twig)
Secure: automatic escaping of dangerous content (by default. Can be turned off with “autoescape off” or using {{ content|raw }}
“The right way”:
Complete separation of business logic and display  MVC
Instead of using PHP, we use an engine specifically built for templating  cannot “hack” business logic into views!
OE NIK 2013

19. Extensible {# base.twig #} {% block body} {% endblock}
{# sub.twig #} {% extends ‘base.twig’ %} {# app/Resources/views/* #} {% block body %} Hello, world! {% endblock %}
{{ parent() }}  append block from parent twig {{ include() }}  includes another template
OE NIK 2013

20. Extensible
OE NIK 2013

21. Three-level inheritance
app/Resources/views/base.html.twig
OE NIK 2013

22. PHP+SQL 3. Files, directories, images TWIG File-based "database"
File-based guestbook
Exercises
OE NIK 2013

23. File format
The entities are typically in the separate rows of the file, the data fields are usually separated by some special character ( \t ; , | )
The only problem is that if a data field contains \n or \t  we forbid these (we could substitute with special letters (weak solution), or we could properly use some special escaping (strong solution, but difficult) )
OE NIK 2013

24. File I/O $path=‘database.txt’;
$database=array(); $rows_array=file($path, FILE_IGNORE_NEW_LINES); foreach ($rows_array as $key=>$row) { $database[]=explode("\t", $row); } //we could use row-by-row operations
$cont=""; foreach ($database as $one_record) { $cont.=implode("\t", $one_record)."\n"; } file_put_contents($path, $cont); // we could use … …
OE NIK 2013

25. HOMEWORK (NOT THIS SEMESTER)
Find out a topic, we need ONE entity with at least FIVE data fields that we want to store (e.g. topic: DVD rental; entity: movies; data fields: title, year, director, price, number_of_copies)
Create a text file that stores 10 entities
Create a PHP script that reads the text file and displays the entities in an HTML table
Find out and program 5 simple questions where you can use simple programming theorems (e.g. What is the most expensive movie, how much movies do we have from 2001), the questions and answers must be displayed below the main table
OE NIK 2013

26. HOMEWORK (FOR POINTS!!!)
Using the original dataset as a source, randomly generate 20 other entities (e.g. 20 random movies) into another array, and display them below the simple questions & answers
Find out and program 3 complex questions that require BOTH arrays (e.g. Generate the union/intersection, or use come complex programming theorems/tasks !)
Create a PDF documentation describing the task you chose and the 8 questions you found out. Do not describe the algorithms step-by-step, only list the questions and an example output!
OE NIK 2013

27. HOMEWORK (FOR POINTS!!!) Deadline: 21st of March, 23:59!
**a link** to the filename and the text must contain your name and your neptun code
The file must be a ZIP/ARJ/RAR/GZ/7Z/XZ file (fullname_neptuncode.zip) that contains:
The full Symfony source
The example TXT file with the 10 entities
The full documentation in PDF form (use some nice formatting, header, footer, etc – must look pretty!  )
OE NIK 2013

28. PHP+SQL 3. Files, directories, images TWIG File-based "database"
File-based guestbook
Exercises
OE NIK 2013

29. Guestbook structure
Actions: guestbook index, add form, file modification
Views: list of entries, data form
Data: ../data/gb.txt
After data modification/insertion, auto-redirect!
Native PHP: header("location: some.php"); die();
Symfony: return $this->redirectToRoute('routeName');
OE NIK 2013

30. File format Data fields: name, email, multi-line text
To define data fields: we use prefix characters
entry text 1 entry text 2
OE NIK 2013

31. Algorithm /gb/add /gb Entries + Link YES /gb/form Display form Save NO
ROUTING
/gb/add
/gb
POST data?
Entries + Link
YES
/gb/form
Display form
Save NO
Error
Redirect + flashbag
OE NIK 2013

32. Sub-parts of the exercise
form.twig: an html form with two single-line textbox (name, ), one multiline textbox (textarea: entry text) and one submit button
List.twig: an html list of guestbook entries
Controller: according to the algorithm on the previous slide
Write the difficult parts:
listAction
addAction
OE NIK 2013

33. ListAction Open file If success, then LOOP, while (not EOF)
Read line, determine first character
If '#', then start new entry, set name
If then set address
Otherwise, set content line without modification
LOOP ends
Instead of line-by-line operations, we could use file(), but we usually need FILE_IGNORE_NEW_LINES, and look out for memory limits (this time: we don’t care)!
OE NIK 2013

34. Save entry
Check Name, , Entry in $_POST Open file for append Append "#" + name + newline Append + + newline Append entry + newline Close file Redirect! ??? What if the entry's first character is # ??? ??? XSS: htmlspecialchars/strip_tags ???
OE NIK 2013

35. LET'S CODE!
OE NIK 2013

36. PHP+SQL 3. Files, directories, images TWIG File-based "database"
File-based guestbook
Exercises
OE NIK 2013

37. Recipe book Create an application to manage a recipe book
The script should have actions to manage the ingredients.txt file: the file contains one ingredient per line; create actions to list them or add a new ingredient
The script should have actions to manage the recipes.txt file: the file should have the entries in the format of: RECIPE_NAME|ingredient1,ingredient2,ingredient3
There should be an action to list all recipes (and the ingredients of the recipes) in a nice-looking table
There should be an action to add a new recipe: first ask the recipe name and the number of ingredients; then input the ingredients (using selects), then save into the file
OE NIK 2013

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