(Xojo Plugin) S3 List Objects in Bucket Folder

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Demonstrates how to retrieve the XML listing of the objects (i.e. files) stored in an Amazon S3 bucket, but just within a particular folder.

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

// In Amazon S3 (Simple Storage Service), there is a distinction between buckets and folders,
// which are both used for organizing and storing data.

// Bucket: A bucket is the top-level container in Amazon S3. It is similar to a directory or folder
// at the root level and acts as a unique namespace for your objects (files). Each bucket must have a globally
// unique name across all of Amazon S3. Buckets are created at the AWS account level and are used to store objects.

// Folder (Prefix): In Amazon S3, folders are not actual physical entities but are virtual constructs called prefixes.
// They are part of the object keys used to organize and group objects within a bucket. Object keys are essentially the
// full path or name of an object, including the folder structure. For example, if you have an object named
// "my-image.jpg" inside a folder named "photos," the object key would be "photos/my-image.jpg."
// Folders are helpful for organizing objects within a bucket and creating a hierarchical structure.

// In reality, S3 does not have a true folder structure. It stores objects in a flat structure with unique keys.
// However, the keys can include slashes ("/") to create a visual separation that resembles a folder structure.
// Various tools and S3 clients interpret the slashes as folder separators and display them accordingly.

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"

// ----------------------------------------------------------------------------------
// List the objects having prefix "images/"
// ----------------------------------------------------------------------------------
Dim strXml As String
strXml = http.S3_ListBucketObjects("chilkat100?prefix=images/")
If (http.LastMethodSuccess <> True) Then
    System.DebugLog(http.LastErrorText)
    Return
End If

System.DebugLog("Response status code = " + Str(http.LastStatus))

Dim xml As New Chilkat.Xml
Dim success As Boolean
success = xml.LoadXml(strXml)
If (success <> True) Then
    System.DebugLog(xml.LastErrorText)
    Return
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
    System.DebugLog(xml.GetXml())
    System.DebugLog("Failed.")
    Return
End If

// A sample response is shown below.
System.DebugLog(xml.GetXml())
System.DebugLog("----")

// Use this online tool to generate parsing code from sample XML: 
// Generate Parsing Code from XML

// Iterate over the bucket items and get information for each..
Dim numItems As Int32
numItems = xml.NumChildrenHavingTag("Contents")
System.DebugLog("Number of bucket items = " + Str(numItems))

Dim itemKey As String
Dim itemSizeDecimalStr As String
Dim lastModTimestamp As String
Dim dt As New Chilkat.CkDateTime

Dim i As Int32
i = 0
While i < numItems
    xml.I = i

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

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

    System.DebugLog(Str(i) + ": " + itemKey + ", " + itemSizeDecimalStr + ", " + Str(dtObj.Day) + "-" + Str(dtObj.Month) _
         + "-" + Str(dtObj.Year) + ":" + Str(dtObj.Hour) + ":" + Str(dtObj.Minute))

    i = i + 1
Wend

// Sample output from the above loop:

// 0: images/africa/, 0, 11-6-2020:20:18
// 1: images/africa/giraffe.jpg, 262769, 11-6-2020:20:20
// 2: images/africa/lion.jpg, 1026769, 11-6-2020:20:20
// 3: images/sea_creatures/starfish123.jpg, 6229, 19-1-2017:10:45
// 4: images/sea_creatures/starfish.jpg, 6229, 19-1-2017:12:7