File.php

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00001 <?PHP
00002 
00003 #
00004 #   FILE:  File.php
00005 #
00006 #   Copyright 2010 Edward Almasy and Internet Scout
00007 #   http://scout.wisc.edu
00008 #
00009 
00010 
00011 class File {
00012 
00013     # ---- PUBLIC INTERFACE --------------------------------------------------
00014 
00015     # status codes (set by constructor and returned by File::Status())
00016     const FILESTAT_OK =             0;
00017     const FILESTAT_COPYERROR =      1;
00018     const FILESTAT_PARAMERROR =     2;
00019     const FILESTAT_ZEROLENGTH =     3;
00020     const FILESTAT_DOESNOTEXIST =   4;
00021     const FILESTAT_UNREADABLE =     5;
00022 
00023     # object constructor
00024     function File($IdOrFileName, $ResourceId = NULL, $FieldId = NULL, 
00025             $DesiredFileName = NULL, $CheckFileLength = TRUE)
00026     {
00027         # assume constructor will succeed
00028         $this->Status = self::FILESTAT_OK;
00029 
00030         # get our own database handle
00031         $DB = new Database();
00032         $this->DB = $DB;
00033 
00034         # if ID supplied
00035         if (is_int($IdOrFileName))
00036         {
00037             # set file ID from supplied value
00038             $this->Id = intval($IdOrFileName);
00039 
00040             # load file info from database
00041             $DB->Query("SELECT * FROM Files WHERE FileId = ".$this->Id);
00042             $this->DBFields = $DB->FetchRow();
00043         }
00044         # else if file name and resource ID and field ID supplied
00045         elseif (strlen($IdOrFileName) && ($ResourceId != NULL) && ($FieldId != NULL))
00046         {
00047             # if file does not exist
00048             $TempFileName = $IdOrFileName;
00049             if (!file_exists($TempFileName) || !is_readable($TempFileName))
00050             {
00051                 # set status indicating appropriate error
00052                 $this->Status = file_exists($TempFileName) 
00053                         ? self::FILESTAT_DOESNOTEXIST : self::FILESTAT_UNREADABLE;
00054             }
00055             else
00056             {
00057                 # if we were asked to check file length and file was zero length
00058                 $FileLength = filesize($TempFileName);
00059                 if ($CheckFileLength && !$FileLength)
00060                 {
00061                     # set status indicating zero length file
00062                     $this->Status = self::FILESTAT_ZEROLENGTH;
00063                 }
00064                 else
00065                 {
00066                     # generate secret string (used to protect from unauthorized download)
00067                     srand((double)microtime() * 1000000);
00068                     $SecretString = sprintf("%04X", rand(1, 30000));
00069     
00070                     # attempt to get file type
00071                     if (function_exists("finfo_open"))
00072                     {
00073                         $FInfoHandle = finfo_open(FILEINFO_MIME);
00074                         $FileType = finfo_file($FInfoHandle, $TempFileName);
00075                         finfo_close($FInfoHandle);
00076                     }
00077                     else
00078                     {
00079                         $FileType = "";
00080                     }
00081     
00082                     # add file info to database
00083                     $BaseFileName = $DesiredFileName 
00084                             ? basename($DesiredFileName) : basename($TempFileName);
00085                     $DB->Query("INSERT INTO Files"
00086                             ." (ResourceId, FieldId, FileName, FileLength, FileType,"
00087                                 ." SecretString)"
00088                             ." VALUES ("
00089                                 .intval($ResourceId).", "
00090                                 .intval($FieldId).", "
00091                                 ."'".addslashes($BaseFileName)."', "
00092                                 .$FileLength.", "
00093                                 ."'".$FileType."', "
00094                                 ."'".$SecretString."')");
00095         
00096                     # retrieve ID of new file
00097                     $this->Id = $DB->LastInsertId("Files");
00098     
00099                     # load file info back in from database
00100                     $DB->Query("SELECT * FROM Files WHERE FileId = ".$this->Id);
00101                     $this->DBFields = $DB->FetchRow();
00102         
00103                     # copy file to storage
00104                     $CopySucceeded = copy($IdOrFileName, $this->GetNameOfStoredFile());
00105         
00106                     # if copy failed
00107                     if (!$CopySucceeded)
00108                     {
00109                         # remove file info from database
00110                         $DB->Query("DELETE FROM Files WHERE FileId = ".$this->Id);
00111         
00112                         # set status indicating constructor failed
00113                         $this->Status = self::FILESTAT_COPYERROR;
00114                     }
00115                 }
00116             }
00117         }
00118         else
00119         {
00120             # set status indicating constructor failed
00121             $this->Status = self::FILESTAT_PARAMERROR;
00122         }
00123     }
00124 
00125     # return object status (used to report errors occurring in constructor)
00126     function Status() {  return $this->Status;  }
00127 
00128     # get various attributes
00129     function Id() {  return $this->Id;  }
00130     function Name() {  return $this->DBFields["FileName"];  }
00131     function GetLength() {  return $this->DBFields["FileLength"];  }
00132     function GetType() {  return $this->DBFields["FileType"];  }
00133 
00134     # get/set various attributes
00135     function Comment($NewValue = DB_NOVALUE)
00136             {  return $this->UpdateValue("FileComment", $NewValue);  }
00137     function FieldId($NewValue = DB_NOVALUE)
00138             {  return $this->UpdateValue("FieldId", $NewValue);  }
00139     function ResourceId($NewValue = DB_NOVALUE)
00140             {  return $this->UpdateValue("ResourceId", $NewValue);  }
00141 
00142     # get MIME type (defaults to "application/octet-stream" if not available)
00143     function GetMimeType()
00144     {
00145         return strlen($this->GetType()) 
00146                 ? $this->GetType() : "application/octet-stream";
00147     }
00148 
00149     # get link for downloading file
00150     function GetLink()
00151     {
00152         return "index.php?P=DownloadFile&Id=".$this->Id;
00153     }
00154 
00155     # delete file (other methods are invalid after calling this!)
00156     function Delete()
00157     {
00158         # remove file entry from DB
00159         $this->DB->Query("DELETE FROM Files WHERE FileId = ".$this->Id);
00160 
00161         # delete file
00162         $FileName = $this->GetNameOfStoredFile();
00163         if (file_exists($FileName))
00164         {
00165             unlink($FileName);
00166         }
00167     }
00168 
00169     # retrieve actual name of stored file
00170     function GetNameOfStoredFile()
00171     {
00172         return sprintf("FileStorage/%06d-%s-%s", 
00173                 $this->Id, $this->DBFields["SecretString"], $this->Name());
00174     }
00175 
00176 
00177     # ---- PRIVATE INTERFACE -------------------------------------------------
00178 
00179     private $DB;
00180     private $Status;
00181     private $Id;
00182     private $DBFields;
00183 
00184     # convenience function to supply parameters to Database->UpdateValue()
00185     private function UpdateValue($FieldName, $NewValue)
00186     {
00187         return $this->DB->UpdateValue("Files", $FieldName, $NewValue,
00188                                "FileId = ".intval($this->Id),
00189                                $this->DBFields, TRUE);
00190     }
00191 }
00192 
00193 
00194 ?>