1 Create a new document in your text editor 2 Add the following script section to the document body Be sure that there is nothing in the fi le before the opening PHP tag 3 Add the following code to the script section to check if the requested fi le exists and is readable $Dir files if (isset($ GET 'filename' )) $FileToGet $Dir stripslashes ($ GET 'filename' ) 254 CHAPTER 5 Working with Files and Directories if (is readable($FileToGet)) else $ErrorMsg Cannot read $FileToGet $ShowErrorPage TRUE else $ErrorMsg No filename specified $ShowErrorPage TRUE if ($ShowErrorPage) 4 Add the following code in the if section of the inner if else statement for the is readable() test to download the fi le header( Content Description File Transfer ) header( Content Type application force download ) header( Content Disposition attachment filename $ GET 'filename' ) header( Content Transfer Encoding base64 ) header( Content Length filesize($FileToGet)) readfile($FileToGet) $ShowErrorPage FALSE 5 Add the following code immediately after the closing PHP tag to show the error page Note the use of advanced escaping to display the Web page output File Download Error There was an error downloading 7 Reopen ViewFiles php Replace the line that reads echo htmlentities($Entry) 255 Uploading and Downloading Files with a line that reads echo htmlentities($Entry) 8 Save ViewFiles php and upload the fi le to the Web server 9 Open the ViewFiles php fi le in your Web browser by entering the following URL http PHP Projects Chapter 05 Chapter ViewFiles php Click one of the highlighted fi lenames Your Web browser should display a save fi le dialog box like the one shown in Figure 5 8 Save the fi le and verify that it downloaded correctly Figure 5 8 The save fi le dialog box for polarbear gif 10 Close your Web browser window 1 Create a new document in your text editor 2 Type the declaration, element, header information, and element Use the strict DTD and Visitor Comments as the content of the element 3 Add the following script section to the document body 4 Add the following code to the script section to store the form data entered $Dir comments if (is dir($Dir)) if (isset($ POST 'save' )) if (empty($ POST 'name' )) $SaveString Unknown Visitor else $SaveString stripslashes ($ POST 'name' ) $SaveString stripslashes ($ POST 'email' ) $SaveString date('r') $SaveString stripslashes ($ POST 'comment' ) $CurrentTime microtime() $TimeArray explode( , $CurrentTime) $TimeStamp (float)$TimeArray 1 (float)$TimeArray 0 In a publicly accessible application on the Internet, using the microtime() function would not be suffi cient to guarantee a unique fi lename, although it is suffi cient to use in this exercise 258 CHAPTER 5 Working with Files and Directories File name is Comment seconds microseconds txt $SaveFileName $Dir Comment $TimeStamp txt if (file put contents($SaveFileName, $SaveString) 0) echo File htmlentities ($SaveFileName) successfully saved else echo There was an error writing htmlentities($SaveFileName) 5 Add the following XHTML form immediately after the closing PHP tag Visitor Comments Your name Your email 6 Save the document as VisitorComments php in the Chapter directory for Chapter 5 and upload the fi le to the server 7 Create a new subdirectory named comments Verify that the comments directory on the Web server has read, write, and execute permissions enabled for user, group, and other 8 Reopen ViewFiles php, change the title to View Comments, and immediately save the fi le as ViewComments php 9 Change the value of $Dir to comments , as follows $Dir comments 10 Convert the code that uses FileDownloader php back to a standard hyperlink, as follows echo htmlentities($Entry) 11 Save ViewComments php in the Chapter directory for Chapter 5 and upload the fi le to the server 12 Open the VisitorComments php fi le in your Web browser by entering the following URL http PHP Projects Chapter 05 Chapter VisitorComments php Attempt For most uses, granting write permission to others is not a safe choice When making this choice, be sure you have considered the security risks Do not grant write permissions unless it is absolutely required 259 Reading and Writing Entire Filesto submit a comment You should receive a message stating whether the comment was saved successfully Figure 5 9 shows an example in which the comment was successfully saved Figure 5 9 A successfully written comment using VisitorComments php 13 After you have successfully submitted one or more comments to the server using the VisitorComments php form, open the ViewComments php fi le in your Web browser by entering the following URL http PHP Projects Chapter 05 Chapter ViewComments php You should see the new fi les in the directory listing Figure 5 10 shows the output of ViewComments php with two comments submitted Figure 5 10 Listing of the comments subdirectory with two saved comments 14 Close your Web browser window 1 Create a new document in your text editor 2 Type the declaration, element, header information, and element Use the strict DTD and Visitor Feedback as the content of the element 3 Add the following script section to the document body 4 Add the following code to the script section to store the form data entered $Dir comments if (is dir($Dir)) $CommentFiles scandir($Dir) foreach ($CommentFiles as $FileName) if (($FileName ) ($FileName )) echo From $FileName echo $Comment file get contents ($Dir $FileName) echo $Comment echo echo 5 Add the following XHTML form immediately before the closing PHP tag Visitor Feedback 6 Save the document as VisitorFeedback php in the Chapter directory for Chapter 5 and upload the fi le to the server 7 Open the VisitorFeedback php fi le in your Web browser by entering the following URL http PHP Projects Chapter 05 Chapter VisitorFeedback php You should see a list of all the user comments from the comments subdirectory Figure 5 12 shows an example with two comments 263 Reading and Writing Entire Files8 Close your Web browser window Figure 5 12 The Visitor Feedback page with two visitor comments If you only want to display the contents of a text fi le, you do not need to use the file get contents() function to assign the contents to a variable and then display the value of the variable as a separate step Instead, you can use the readfile() function discussed earlier to display the contents of a text fi le to a Web browser For example, the following example uses the readfile() function to accomplish the same task as the file get contents() example you saw earlier readfile( sfweather txt ) At times, text fi les are used to store individual lines of data, where each line represents a single unit of information e easiest way to read the contents of a text fi le that stores data on individual lines is to use the file() function, which reads the entire contents of a fi le into an indexed array e file() function automatically recognizes whether the lines in a text fi le end in , , or Each individual line in the text fi le is assigned as the value of an element You pass to the file() function the name of the text fi le enclosed in quotation marks For example, the weather service that stores daily weather reports may also store average daily high, low, and mean temperatures, separated by commas, on individual lines in a single text fi le e following code uses the file put contents() function to write the temperatures for the fi rst week in January to a text fi le named s anaverages txt $January 61, 42, 48 $January 62, 41, 49 264 CHAPTER 5 Working with Files and Directories Feedback Mozilla Firefox 1 xl File Edit View History Bookmarks lools Help C j 1 0 http student200 ucb sephone us PHP frojects Chapter 05 Chapter VisitorFeedback php Visitor Feedback From Comment l240187766 2 txt Joseph Michaels jm0example com Sun, 19 Apr 2009 20 36 06 0400 Ireally like your sice From Comment l240187812 43 txt Nancy Daniels nancy danielsSexample edu Sun, 19 Apr 2009 20 36 52 0400 Ireally don'c like your srce j Done$January 62, 41, 49 $January 64, 40, 51 $January 69, 44, 55 $January 69, 45, 52 $January 67, 46, 54 file put contents( sfjanaverages txt , $January) e fi rst statement in the following code uses the file() function to read the contents of the s anaverages txt fi le into an indexed array named $JanuaryTemps e for statement then loops through each element in $JanuaryTemps and calls the explode() function from Chapter 3 to split each element at the comma into another array named $CurDay e high, low, and mean averages in the $CurDay array are then displayed with echo statements Figure 5 13 shows the output $JanuaryTemps file( sfjanaverages txt ) for ($i 0 $i

Question

1  Create a new document in your text editor  2  Add the following script section to the document body  Be sure that there is nothing in the fi le before the opening PHP tag  3  Add the following code to the script section to check if the requested fi le exists and is readable  $Dir    files   if (isset($ GET 'filename' ))   $FileToGet   $Dir         stripslashes ($ GET 'filename' )  254 CHAPTER 5 Working with Files and Directories if (is readable($FileToGet))     else   $ErrorMsg    Cannot read   $FileToGet     $ShowErrorPage   TRUE      else   $ErrorMsg    No filename specified   $ShowErrorPage   TRUE    if ($ShowErrorPage)   4  Add the following code in the if section of the inner if   else statement for the is readable() test to download the fi le  header( Content Description  File Transfer )  header( Content Type  application force download )  header( Content Disposition  attachment  filename       $ GET 'filename'        )  header( Content Transfer Encoding  base64 )  header( Content Length      filesize($FileToGet))  readfile($FileToGet)  $ShowErrorPage   FALSE  5  Add the following code immediately after the closing PHP tag to show the error page  Note the use of advanced escaping to display the Web page output  File Download Error There was an error downloading     7  Reopen ViewFiles php  Replace the line that reads  echo      htmlentities($Entry)       255 Uploading and Downloading Files with a line that reads  echo      htmlentities($Entry)       8  Save ViewFiles php and upload the fi le to the Web server  9  Open the ViewFiles php fi le in your Web browser by entering the following URL  http     PHP Projects Chapter 05 Chapter ViewFiles php  Click one of the highlighted fi lenames  Your Web browser should display a save fi le dialog box like the one shown in Figure 5 8  Save the fi le and verify that it downloaded correctly  Figure 5 8 The save fi le dialog box for polarbear gif 10  Close your Web browser window  1  Create a new document in your text editor  2  Type the declaration, element, header information, and element  Use the strict DTD and Visitor Comments as the content of the element  3  Add the following script section to the document body  4  Add the following code to the script section to store the form data entered  $Dir    comments   if (is dir($Dir))   if (isset($ POST 'save' ))   if (empty($ POST 'name' )) $SaveString    Unknown Visitor    else $SaveString   stripslashes ($ POST 'name' )        $SaveString    stripslashes ($ POST 'email' )        $SaveString    date('r')        $SaveString    stripslashes ($ POST 'comment' )  $CurrentTime   microtime()  $TimeArray   explode(   , $CurrentTime)  $TimeStamp   (float)$TimeArray 1    (float)$TimeArray 0   In a publicly accessible application on the Internet, using the microtime() function would not be suffi cient to guarantee a unique fi lename, although it is suffi cient to use in this exercise  258 CHAPTER 5 Working with Files and Directories    File name is   Comment seconds  microseconds txt     $SaveFileName    $Dir Comment $TimeStamp  txt   if (file put contents($SaveFileName, $SaveString) 0) echo  File       htmlentities ($SaveFileName)       successfully saved     else echo  There was an error writing       htmlentities($SaveFileName)               5  Add the following XHTML form immediately after the closing PHP tag  Visitor Comments Your name  Your email  6  Save the document as VisitorComments php in the Chapter directory for Chapter 5 and upload the fi le to the server  7  Create a new subdirectory named comments  Verify that the comments directory on the Web server has read, write, and execute permissions enabled for user, group, and other  8  Reopen ViewFiles php, change the title to View Comments, and immediately save the fi le as ViewComments php  9  Change the value of $Dir to  comments , as follows  $Dir    comments   10  Convert the code that uses FileDownloader php back to a standard hyperlink, as follows  echo      htmlentities($Entry)      11  Save ViewComments php in the Chapter directory for Chapter 5 and upload the fi le to the server  12  Open the VisitorComments php fi le in your Web browser by entering the following URL  http     PHP Projects Chapter 05 Chapter VisitorComments php  Attempt For most uses, granting write permission to others is not a safe choice  When making this choice, be sure you have considered the security risks  Do not grant write permissions unless it is absolutely required  259 Reading and Writing Entire Filesto submit a comment  You should receive a message stating whether the comment was saved successfully  Figure 5 9 shows an example in which the comment was successfully saved  Figure 5 9 A successfully written comment using VisitorComments php 13  After you have successfully submitted one or more comments to the server using the VisitorComments php form, open the ViewComments php fi le in your Web browser by entering the following URL  http     PHP Projects  Chapter 05 Chapter ViewComments php  You should see the new fi les in the directory listing  Figure 5 10 shows the output of ViewComments php with two comments submitted  Figure 5 10 Listing of the comments subdirectory with two saved comments 14  Close your Web browser window  1  Create a new document in your text editor  2  Type the declaration, element, header information, and element  Use the strict DTD and Visitor Feedback as the content of the element  3  Add the following script section to the document body  4  Add the following code to the script section to store the form data entered  $Dir    comments   if (is dir($Dir))   $CommentFiles   scandir($Dir)  foreach ($CommentFiles as $FileName)   if (($FileName       )    ($FileName        ))   echo  From $FileName    echo      $Comment   file get contents ($Dir         $FileName)  echo $Comment  echo      echo            5  Add the following XHTML form immediately before the closing PHP tag  Visitor Feedback 6  Save the document as VisitorFeedback php in the Chapter directory for Chapter 5 and upload the fi le to the server  7  Open the VisitorFeedback php fi le in your Web browser by entering the following URL  http      PHP Projects Chapter 05 Chapter VisitorFeedback php  You should see a list of all the user comments from the comments subdirectory  Figure 5 12 shows an example with two comments  263 Reading and Writing Entire Files8  Close your Web browser window  Figure 5 12 The Visitor Feedback page with two visitor comments If you only want to display the contents of a text fi le, you do not need to use the file get contents() function to assign the contents to a variable and then display the value of the variable as a separate step  Instead, you can use the readfile() function discussed earlier to display the contents of a text fi le to a Web browser  For example, the following example uses the readfile() function to accomplish the same task as the file get contents() example you saw earlier  readfile( sfweather txt )  At times, text fi les are used to store individual lines of data, where each line represents a single unit of information  e easiest way to read the contents of a text fi le that stores data on individual lines is to use the file() function, which reads the entire contents of a fi le into an indexed array  e file() function automatically recognizes whether the lines in a text fi le end in , , or   Each individual line in the text fi le is assigned as the value of an element  You pass to the file() function the name of the text fi le enclosed in quotation marks  For example, the weather service that stores daily weather reports may also store average daily high, low, and mean temperatures, separated by commas, on individual lines in a single text fi le  e following code uses the file put contents() function to write the temperatures for the fi rst week in January to a text fi le named s anaverages txt  $January    61, 42, 48    $January     62, 41, 49    264 CHAPTER 5 Working with Files and Directories   Feedback   Mozilla Firefox 1 xl File Edit View History Bookmarks lools Help   C  j 1 0 http   student200 ucb sephone us PHP frojects Chapter 05 Chapter VisitorFeedback php  Visitor Feedback From Comment l240187766 2 txt Joseph Michaels jm0example com Sun, 19 Apr 2009 20 36 06  0400 Ireally like your sice  From Comment l240187812 43 txt Nancy Daniels nancy danielsSexample edu Sun, 19 Apr 2009 20 36 52  0400 Ireally don'c like your srce  j Done$January     62, 41, 49    $January     64, 40, 51    $January     69, 44, 55    $January     69, 45, 52    $January     67, 46, 54    file put contents( sfjanaverages txt , $January)  e fi rst statement in the following code uses the file() function to read the contents of the s anaverages txt fi le into an indexed array named $JanuaryTemps    e for statement then loops through each element in $JanuaryTemps   and calls the explode() function from Chapter 3 to split each element at the comma into another array named $CurDay  e high, low, and mean averages in the $CurDay array are then displayed with echo statements  Figure 5 13 shows the output  $JanuaryTemps   file( sfjanaverages txt )  for ($i 0  $i

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1. Create a new document in your text editor. 2. Add the following script section to the document body. Be sure that there is nothing