Objective-C

Get GMail Message Metadata

See more GMail REST API Examples

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

#import <CkoHttp.h>
#import <CkoJsonObject.h>
#import <CkoHttpResponse.h>
#import <NSString.h>

BOOL success = NO;

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

CkoHttp *http = [[CkoHttp alloc] init];

http.AuthToken = @"ACCESS_TOKEN";

http.Accept = @"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.
CkoJsonObject *jsonMsgIds = [[CkoJsonObject alloc] init];
success = [jsonMsgIds LoadFile: @"qa_data/json/gmail_message_ids.json"];

CkoHttpResponse *resp = [[CkoHttpResponse alloc] init];

NSString *id = 0;
int i = 0;
int count_i = [[jsonMsgIds SizeOfArray: @"messages"] intValue];
while (i < count_i) {
    jsonMsgIds.I = [NSNumber numberWithInt: i];
    id = [jsonMsgIds StringOf: @"messages[i].id"];

    //  Get the metadata for this message ID.
    [http SetUrlVar: @"id" value: id];

    success = [http HttpNoBody: @"GET" url: @"https://www.googleapis.com/gmail/v1/users/userId/messages/{$id}?format=metadata" response: resp];
    if (success == NO) {
        NSLog(@"%@",http.LastErrorText);
        return;
    }

    NSLog(@"%@%d",@"Response Status Code: ",[resp.StatusCode intValue]);

    CkoJsonObject *jsonResponse = [[CkoJsonObject alloc] init];
    [jsonResponse Load: resp.BodyStr];
    jsonResponse.EmitCompact = NO;
    NSLog(@"%@",[jsonResponse Emit]);

    if ([resp.StatusCode intValue] != 200) {
        NSLog(@"%@",@"Failed.");
        return;
    }

    i = i + 1;
}

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