(VB.NET UWP/WinRT) Amazon S3 List More than 1000 Objects in Bucket

S3 limits the size of the "List Objects" response to 1000 objects. To retrieve a listing of all of the objects in a bucket containing more than 1000 objects, we'll need to send several requests using continuation tokens.

Chilkat Universal Windows Platform (UWP) / WinRT Downloads Chilkat for the Universal Windows Platform (UWP)

' This example assumes the Chilkat HTTP API to have been previously unlocked.
' See Global Unlock Sample for sample code.

Dim http As New Chilkat.Http

' Insert your access key here:
http.AwsAccessKey = "AWS_ACCESS_KEY"

' Insert your secret key here:
http.AwsSecretKey = "AWS_SECRET_KEY"


' For the example, we'll get a listing containing approx. 25 objects
' using continuation tokens with an artificially low max-keys set to 5.
' (You may omit the max-keys query parameter to get the default 1000 maximum
' number of keys per request.)

Dim sbContinuationToken As New Chilkat.StringBuilder
Dim bGetMore As Boolean = True
Dim sbUri As New Chilkat.StringBuilder
Dim xml As New Chilkat.Xml
Dim success As Boolean
Dim itemKey As String
Dim itemSize As Integer
Dim lastModTimestamp As String
Dim dt As New Chilkat.CkDateTime

While bGetMore = True

    ' Make sure to set the "list-type" query param equal to "2".
    ' This chooses the GET Bucket (List Objects) Version 2 of the method.
    sbUri.SetString("chilkat100?list-type=2&max-keys=5")
    If (sbContinuationToken.Length > 0) Then
        sbUri.Append("&continuation-token=")
        sbUri.Append(sbContinuationToken.GetEncoded("url","utf-8"))
    End If

    Dim strXml As String = Await http.S3_ListBucketObjectsAsync(sbUri.GetAsString())
    If (http.LastMethodSuccess <> True) Then
        Debug.WriteLine(http.LastErrorText)
        Exit Sub
    End If



    Debug.WriteLine("Response status code = " & http.LastStatus)

    success = xml.LoadXml(strXml)
    If (success <> True) Then
        Debug.WriteLine(xml.LastErrorText)
        Exit Sub
    End If

    ' If the response status code was not 200, then the XML response is not a 
    ' listing of objects, but instead contains error information.
    If (http.LastStatus <> 200) Then
        Debug.WriteLine(xml.GetXml())
        Debug.WriteLine("Failed.")
        Exit Sub
    End If


    ' If this is not the final response, then we'll get an XML response that begins
    ' like this.  (The IsTruncated child will be "true", and the NextContinuationToken
    ' will have a value to be used in the next request.)
    ' 	<?xml version="1.0" encoding="UTF-8" ?>
    ' 	<ListBucketResult xmlns="http://s3.amazonaws.com/doc/2006-03-01/">
    ' 	    <Name>chilkat100</Name>
    ' 	    <Prefix />
    ' 	    <NextContinuationToken>1Mlcx+W9OKsr8cxp3DP6r71wgsTUMj0vqlntWoaJKNbYdrauLdf40LsUdBeSYGFhzbGIHdcf5DSLcEBWbqG+1fW1UcQkUW1V4qgQONAKOwb8y8vOLJAQ8iQ==</NextContinuationToken>
    ' 	    <KeyCount>5</KeyCount>
    ' 	    <MaxKeys>5</MaxKeys>
    ' 	    <IsTruncated>true</IsTruncated>
    ' 	

    ' Iterate over the bucket items in this chunk get information for each..
    Dim numItems As Integer = xml.NumChildrenHavingTag("Contents")
    Debug.WriteLine("Number of bucket items = " & numItems)

    Dim i As Integer = 0
    While i < numItems
        xml.I = i

        itemKey = xml.GetChildContent("Contents[i]|Key")
        itemSize = xml.GetChildIntValue("Contents[i]|Size")
        lastModTimestamp = xml.GetChildContent("Contents[i]|LastModified")

        dt.SetFromRfc822(lastModTimestamp)
        ' Get a local date/time.
        Dim bLocal As Boolean = True
        Dim dtObj As Chilkat.DtObj = dt.GetDtObj(bLocal)

        Debug.WriteLine(i & ": " & itemKey & ", " & itemSize & ", " & dtObj.Day & "-" & dtObj.Month & "-" & dtObj.Year _
             & ":" & dtObj.Hour & ":" & dtObj.Minute)


        i = i + 1
    End While

    ' Check IsTruncated.
    bGetMore = False
    If (xml.ChildContentMatches("IsTruncated","true",True) = True) Then
        sbContinuationToken.SetString(xml.GetChildContent("NextContinuationToken"))
        If (sbContinuationToken.Length > 0) Then
            bGetMore = True
        End If

    End If


End While

' The output of this example (when tested) was:

' Response status code = 200
' Number of bucket items = 5
' 0: Abc.ics, 1833, 25-5-2011:9:53
' 1: Corpse Bride film poster.jpg, 53481, 6-9-2016:13:32
' 2: chiliPepper.gif, 7718, 12-3-2017:12:18
' 3: chilkatdude.jpg, 35137, 20-5-2011:16:14
' 4: cloud.search/dfe/indexer/pscc/2016/3/28/id,x-2-15-0-25-87-0.json, 1238, 2-4-2016:12:0
' Response status code = 200
' Number of bucket items = 5
' 0: cloud.search/dfe/indexer/pscc/2016/3/28/idx-2-15-0-25-87-0.json, 1238, 2-4-2016:11:33
' 1: dude.gif, 6373, 25-5-2011:17:29
' 2: french.txt, 47, 12-3-2017:12:18
' 3: hamlet.xml, 279658, 2-5-2016:12:21
' 4: hamlet_play.xml, 279658, 20-3-2017:8:22
' Response status code = 200
' Number of bucket items = 5
' 0: images/sea_creatures/starfish123.jpg, 6229, 19-1-2017:10:45
' 1: images/sea_creatures/starfishåäö.jpg, 6229, 19-1-2017:12:7
' 2: new folder/, 0, 26-11-2014:12:36
' 3: new_starfish.jpg, 6229, 20-3-2017:8:22
' 4: pigs.xml, 2804, 20-3-2017:8:22
' Response status code = 200
' Number of bucket items = 5
' 0: somethingBig.zip, 13089458, 26-9-2016:9:29
' 1: starfish.jpg, 6229, 12-3-2017:12:18
' 2: starfish/, 0, 10-11-2014:10:7
' 3: starfish/starfish.jpg, 6229, 10-11-2014:10:8
' 4: starfish/starfish2.jpg, 6229, 19-11-2014:10:36
' Response status code = 200
' Number of bucket items = 5
' 0: starfish/starfish3.jpg, 6229, 24-11-2014:14:33
' 1: starfish2.jpg, 5987, 20-4-2012:12:6
' 2: starfish3.jpg, 5987, 11-4-2012:7:10
' 3: starfishA.jpg, 6229, 10-5-2016:8:44
' 4: starfishCust.jpg, 6229, 12-11-2014:18:25
' Response status code = 200
' Number of bucket items = 1
' 0: xyz.ics, 1833, 25-5-2011:8:52
' 
'