(Visual FoxPro) Chilkat Zip API Concepts

This example helps clarify some common misconceptions w/ using the Chilkat Zip API.

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

LOCAL loZip
LOCAL lnSuccess
LOCAL lnSaveExtraPath
LOCAL loEntry
LOCAL i
LOCAL n

* This example requires the Chilkat API to have been previously unlocked.
* See Global Unlock Sample for sample code.

* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.Zip')
loZip = CreateObject('Chilkat.Zip')

* To clarify some concepts, this example will create a new .zip containing 2 files.

* The NewZip method is called to initialize the zip object to a new and empty state.
* It does not actually create the .zip file.  It simply intializes the object.
* if the zip object did not contain anything previously, then this method could be skipped
* altogether.  It has the side-effect of setting the zip.FileName property.
lnSuccess = loZip.NewZip("test.zip")
IF (lnSuccess <> 1) THEN
    ? loZip.LastErrorText
    RELEASE loZip
    CANCEL
ENDIF

* The FileName property should now contain "test.zip".  This is the name of the .zip
* that is written when WriteZip or WriteZipAndClose is called.
? "zip filename = " + loZip.FileName

* When a file is "appended" to the zip object, we are really just appending a reference
* to the file in the filesystem.  A "zip entry" is added to the zip object and this entry
* can be one of several types.  It can point to a file.  It can contain uncompressed binary
* or text data, it can point to an entry in the already-opened zip (if we had called OpenZip 
* instead), etc.  

* Now.. add a reference to a single file by calling AppendOneFileOrDir
* Note: On Windows, forward slashes are equivalent to backslashes
lnSaveExtraPath = 0
lnSuccess = loZip.AppendOneFileOrDir("/temp/abc123/HelloWorld123.txt",lnSaveExtraPath)
IF (lnSuccess <> 1) THEN
    ? loZip.LastErrorText
    RELEASE loZip
    CANCEL
ENDIF

* We now have a zip object with one entry, which points to the file /temp/abc123/HelloWorld123.txt
* If desired, we could change the filename of the zip entry so that when the zip is written,
* the file has a different name:
loEntry = loZip.GetEntryByIndex(0)
loEntry.FileName = "helloWorld.txt"
RELEASE loEntry

* When the zip is actually written, the entry's data will stream from /temp/abc123/HelloWorld123.txt
* and be compressed into an entry within the .zip having the filename "helloWorld.txt"

* Now add another entry, this time from a string containing the file content:
loEntry = loZip.AppendString2("HelloWorld2.txt","hello world!","utf-8")
RELEASE loEntry

* Examine the entries in the zip so far..
* Each entry can be one of the following types:

* 0 -- Mapped Entry: An entry in an existing Zip file.
* 1 -- File Entry: A file not yet in memory, but referenced. 
*      These entries are added by calling AppendFiles, AppendFilesEx, AppendOneFileOrDir, etc.
* 2 -- Data Entry: An entry containing uncompressed data from memory. 
*      These entries are added by calling AppendData, AppendString, etc.
* 3 -- Null Entry: An entry that no longer exists in the .zip.
* 4 -- New Directory Entry: A directory entry added by calling AppendNewDir. 

n = loZip.NumEntries
FOR i = 0 TO n - 1

    loEntry = loZip.GetEntryByIndex(i)
    ? loEntry.FileName + ", type=" + STR(loEntry.EntryType)
    RELEASE loEntry
NEXT

* Write the "test.zip" file.
lnSuccess = loZip.WriteZip()
IF (lnSuccess <> 1) THEN
    ? loZip.LastErrorText
    RELEASE loZip
    CANCEL
ENDIF

* Our zip object still contains 2 entries, but now they point to the entries within the 
* test.zip  (We called WriteZip, which writes the .zip but does not close it.  Instead,
* the entries of the zip object are updated to become "mapped" entries.
* For example:

n = loZip.NumEntries
FOR i = 0 TO n - 1

    loEntry = loZip.GetEntryByIndex(i)
    ? loEntry.FileName + ", type=" + STR(loEntry.EntryType)
    RELEASE loEntry
NEXT

* Finally, close the zip
loZip.CloseZip()

RELEASE loZip