Read and write files example
From DataFlex Wiki
Listing for the "Read and write files example" view:
Use Windows.pkg
Use DFClient.pkg
Use cCharTranslate.pkg
Use seq_chnl.pkg
Use File_dlg.pkg
Use cTextEdit.pkg
Deferred_View Activate_oReadWriteFiles for ;
Object oReadWriteFiles is a dbView
Set Border_Style to Border_Thick
Set Size to 155 533
Set Location to 1 2
Set Label to "Read and write files example"
Property String psMyFile
Property Integer piOldSize
// This is what provides the means to encode/decode base64:
Object oTrans is a cCharTranslate
End_Object
// These two functions - ReadMyFile and WriteMyFile - are where the work
// gets done.
Function ReadMyFile String sFilePathName Returns Boolean
Integer iChn
UChar[] ucaData
String sFile
Boolean bExists
// For timing test
DateTime dtStart dtEnd
Timespan tsDiff
// Check file exists
File_Exist sFilePathName bExists
If not bExists Begin
Send UserError ('File "' + sFilePathName + '" was not found') "File not found"
Function_Return False
End
Get Seq_New_Channel to iChn
Direct_Input channel iChn ("Binary:" + sFilePathName)
If not (SeqEof) Begin
// Timing test
Move (CurrentDateTime()) to dtStart
Read_Block channel iChn ucaData -1
Move (Base64EncodeUCharArray(oTrans(Self), ucaData)) to ucaData
Set_Argument_Size (SizeOfArray(ucaData) + 1)
Move (UCharArrayToString(ucaData)) to sFile
// Timeing test
Move (CurrentDateTime()) to dtEnd
Move (dtEnd - dtStart) to tsDiff
// Showln ("Read: " * String(SpanTotalMilliseconds(tsDiff)) + "ms")
End
Else Begin
Send UserError ('File "' + sFilePathName + '" does not exist or was empty') "File Error"
Function_Return False
End
Close_Output channel iChn
Send Seq_Release_Channel iChn
Set psMyFile to sFile
Function_Return True
End_Function
Function WriteMyFile String sFilePathName Returns Boolean
Integer iChn iPos iResp
UChar[] ucaFile
String sPath sDir sFile
Boolean bExists
// For timing test
DateTime dtStart dtEnd
Timespan tsDiff
Move (RightPos("\", sFilePathName)) to iPos
If not iPos Begin
Send UserError "Could not find folder" "Folder Error"
Function_Return False
End
Move (Left(sFilePathName, (iPos - 1))) to sPath
File_Exist sPath bExists
If not bExists Begin
Send UserError ('Folder "' + sPath + '" does not exist') "Folder Error"
Function_Return False
End
Move (Right(sFilePathName, (Length(sFilePathName) - iPos))) to sFile
File_Exist sFilePathName bExists
If bExists Begin
Move (Right(sFilePathName, (Length(sFilePathName) - iPos))) to sFile
Get YesNo_Box ;
('The file "' + sFile + '" already exists in folder' * sPath + '. Do you wish to overwrite it?') ;
"Overwrite file?" to iResp
If (iResp = MBR_NO) ;
Function_Return False
End
Move (StringToUCharArray(psMyFile(Self))) to ucaFile
Move (Base64DecodeUCharArray(oTrans(Self), ucaFile)) to ucaFile
// If some other program has the file open (and in some cases, has even
// previously had the file open), writing to it may fail, so we catch
// that error in order to deal with it ourselves and return "failure"
// rather "success", resetting it after the write operation, and use the
// ERR global indicator to detect the problem.
Send Ignore_Error of Error_Object_Id 32
Move False to Err
// Timing test
Move (CurrentDateTime()) to dtStart
Get Seq_New_Channel to iChn
Direct_Output channel iChn ("Binary:" + sFilePathName)
Write channel iChn ucaFile
Close_Output channel iChn
Send Seq_Release_Channel iChn
Send Trap_Error of Error_Object_Id 32
// Timing test
Move (CurrentDateTime()) to dtEnd
Move (dtEnd - dtStart) to tsDiff
// Showln ("Write:" * String(SpanTotalMilliseconds(tsDiff)) + "ms")
If (Err) Begin
Send UserError ('There was an error writing to file "' + sFilePathName + '"') "Write Error"
Function_Return False
End
Function_Return True
End_Function
// The user interface...
Object oOpenDialog is a OpenDialog
End_Object
Object oSaveAsDialog is a SaveAsDialog
End_Object
Object oRead is a Form
Set Size to 13 390
Set Location to 3 86
Set Label to "File path-name to read:"
Set psToolTip to "File path-name to read"
Set Label_Justification_Mode to JMode_Right
Set Label_Col_Offset to 2
Set Value to ;
"C:\Program Files (x86)\DataFlex 19.1\Documentation\Installation_and_Environment_Guide.pdf"
Set Prompt_Button_Mode to PB_PromptOn
Set peAnchors to anTopLeftRight
Procedure Prompt
Boolean bOK
String sFile
Get Show_Dialog of oOpenDialog to bOK
If bOK Begin
Get File_Name of oOpenDialog to sFile
Set Value to sFile
End
End_Procedure
End_Object
Object oDoRead is a Button
Set Size to 14 47
Set Location to 3 480
Set Label to "Read file"
Set peAnchors to anTopRight
Procedure OnClick
String sFile
Boolean bOK
Integer iOldSize iNewSize
Get_Argument_Size to iOldSize
Set piOldSize to iOldSize
Set Value of oBase64File to ""
Get Value of oRead to sFile
Get ReadMyFile sFile to bOK
Set Enabled_State of oWrite to bOK
Set Enabled_State of oDoWrite to bOK
If bOK Begin
Get_Argument_Size to iNewSize
Set piMaxChars of oBase64File to iNewSize
Set Value of oBase64File to (If(bOK, psMyFile(Self), ""))
End
Else Begin
Set_Argument_Size (piOldSize(Self))
Set piMaxChars of oBase64File to (piOldSize(Self))
End
Send Info_Box ('File "' + sFile + ;
If(bOK, '" was read successfully', '" could not be read')) ;
(If(bOK, "Success", "Failure"))
End_Procedure
End_Object
Object oWrite is a Form
Set Size to 13 390
Set Location to 20 86
Set Label to "File path-name to write:"
Set Label_Justification_Mode to JMode_Right
Set Label_Col_Offset to 2
Set Enabled_State to False
Set Value to "C:\Temp\MyTestFile.pdf"
Set Prompt_Button_Mode to PB_PromptOn
Set peAnchors to anTopLeftRight
Procedure Prompt
Boolean bOK
String sFile
Get Show_Dialog of oSaveAsDialog to bOK
If bOK Begin
Get File_Name of oSaveAsDialog to sFile
Set Value to sFile
End
End_Procedure
End_Object
Object oDoWrite is a Button
Set Size to 14 47
Set Location to 20 480
Set Label to "Write file"
Set Enabled_State to False
Set peAnchors to anTopRight
Procedure OnClick
String sFile
Boolean bOK
Get Value of oWrite to sFile
If (sFile = "") Begin
Send Info_Box "You must enter a file path and name to write to" "Enter Filepath"
Procedure_Return
End
Get WriteMyFile sFile to bOK
Set Enabled_State of oWrite to (not(bOK))
Set Enabled_State of oDoWrite to (not(bOK))
If bOK Begin
Set Value of oBase64File to ""
Set psMyFile to ""
Set_Argument_Size (piOldSize(Self))
Set piMaxChars of oBase64File to (piOldSize(Self))
End
Send Info_Box ('File "' + sFile + ;
If(bOK, '" was written successfully', '" was not written')) ;
(If(bOK, "Success", "Failure"))
End_Procedure
End_Object
Object oBase64File is a cTextEdit
Set Size to 101 520
Set Location to 46 6
Set Read_Only_State to True
Set Label to "Base64 Encoded File (will be gibberish... unless vous parlez base64!):"
Set peAnchors to anAll
End_Object
CD_End_Object
