(DataFlex) Get GMail Message Metadata

Demonstrates how to get the metadata for each message in a list of message IDs.

Note: This example requires Chilkat v11.0.0 or greater.

For more information, see https://developers.google.com/gmail/api/v1/reference/users/messages/get

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

Use ChilkatAx-win32.pkg

Procedure Test
    Boolean iSuccess
    Handle hoHttp
    Handle hoJsonMsgIds
    Variant vResp
    Handle hoResp
    String sId
    Integer i
    Integer iCount_i
    Handle hoJsonResponse
    String sTemp1
    Integer iTemp1

    Move False To iSuccess

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

    Get Create (RefClass(cComChilkatHttp)) To hoHttp
    If (Not(IsComObjectCreated(hoHttp))) Begin
        Send CreateComObject of hoHttp
    End

    Set ComAuthToken Of hoHttp To "ACCESS_TOKEN"

    Set ComAccept Of hoHttp To "application/json"

    // Let's say we have the following JSON containing a list of message ID's

    // {
    //   "messages": [
    //     {
    //       "id": "1712bc1dc22da2a2",
    //       "threadId": "1712bc1dc22da2a2"
    //     },
    //     {
    //       "id": "1712b94fa2168040",
    //       "threadId": "1712b94fa2168040"
    //     },
    //     {
    //       "id": "1711e4bd96ded05e",
    //       "threadId": "1711e4bd96ded05e"
    //     },
    //     {
    //       "id": "1711de0d119e751e",
    //       "threadId": "1711de0d119e751e"
    //     },
    //     {
    //       "id": "1711c81a43050f59",
    //       "threadId": "1711c81a43050f59"
    //     },
    //     {
    //       "id": "1711c2c1516abce5",
    //       "threadId": "1711c2c1516abce5"
    //     },
    //     {
    //       "id": "1711c161e655c915",
    //       "threadId": "1711c161e655c915"
    //     },
    //     {
    //       "id": "171199c6e454558c",
    //       "threadId": "171199c6e454558c"
    //     },
    //     {
    //       "id": "17119474c8aa248e",
    //       "threadId": "17119474c8aa248e"
    //     }
    //   ],
    //   "nextPageToken": "16710921492249671162",
    //   "resultSizeEstimate": 309
    // }

    // Normally your program would have the above JSON in a string variable (obtained from a previous call to get
    // a list of message IDs from a GMail mailbox).  In this example, we'll load the JSON from a file.
    Get Create (RefClass(cComChilkatJsonObject)) To hoJsonMsgIds
    If (Not(IsComObjectCreated(hoJsonMsgIds))) Begin
        Send CreateComObject of hoJsonMsgIds
    End
    Get ComLoadFile Of hoJsonMsgIds "qa_data/json/gmail_message_ids.json" To iSuccess

    Get Create (RefClass(cComChilkatHttpResponse)) To hoResp
    If (Not(IsComObjectCreated(hoResp))) Begin
        Send CreateComObject of hoResp
    End

    Move 0 To i
    Get ComSizeOfArray Of hoJsonMsgIds "messages" To iCount_i
    While (i < iCount_i)
        Set ComI Of hoJsonMsgIds To i
        Get ComStringOf Of hoJsonMsgIds "messages[i].id" To sId

        // Get the metadata for this message ID.
        Get ComSetUrlVar Of hoHttp "id" sId To iSuccess

        Get pvComObject of hoResp to vResp
        Get ComHttpNoBody Of hoHttp "GET" "https://www.googleapis.com/gmail/v1/users/userId/messages/{$id}?format=metadata" vResp To iSuccess
        If (iSuccess = False) Begin
            Get ComLastErrorText Of hoHttp To sTemp1
            Showln sTemp1
            Procedure_Return
        End

        Get ComStatusCode Of hoResp To iTemp1
        Showln "Response Status Code: " iTemp1

        Get Create (RefClass(cComChilkatJsonObject)) To hoJsonResponse
        If (Not(IsComObjectCreated(hoJsonResponse))) Begin
            Send CreateComObject of hoJsonResponse
        End
        Get ComBodyStr Of hoResp To sTemp1
        Get ComLoad Of hoJsonResponse sTemp1 To iSuccess
        Set ComEmitCompact Of hoJsonResponse To False
        Get ComEmit Of hoJsonResponse To sTemp1
        Showln sTemp1

        Get ComStatusCode Of hoResp To iTemp1
        If (iTemp1 <> 200) Begin
            Showln "Failed."
            Procedure_Return
        End

        Move (i + 1) To i
    Loop

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


End_Procedure