(Objective-C) Manage Cloud Storage Bucket Labels

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Demonstrates how to add, update, and delete labels for a Cloud Storage bucket.

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

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

// This example uses a previously obtained access token having permission for the 
// scope "https://www.googleapis.com/auth/cloud-platform"

// In this example, Get Google Cloud Storage OAuth2 Access Token, 
// the service account access token was saved to a text file.  This example fetches the access token from the file..
CkoStringBuilder *sbToken = [[CkoStringBuilder alloc] init];
[sbToken LoadFile: @"qa_data/tokens/googleCloudStorageAccessToken.txt" charset: @"utf-8"];

// ---- Step 1
// Create the JSON body of the PATCH request that will be sent.
// This specifies labels to be added, updated, and/or deleted.
// (To delete a label, set its value equal to null.)

// {
//   "labels": {
//     "new_label_key": "new_label_value",
//     "existing_label_key": "updated_label_value",
//     "old_label_key": null
//   }
// }

// ---------
// Important
// ---------
// You can apply multiple labels to each bucket, with a maximum of 64 labels per bucket.

//     - Keys and values cannot be longer than 63 characters each.
//     - Keys and values can only contain lowercase letters, numeric characters, underscores, and dashes. International characters are allowed.
//     - Label keys must start with a lowercase letter and international characters are allowed.
//     - Label keys cannot be empty.

// Build JSON to update labels.
// 
// During the testing of this example, my bucket already has the following labels:
// {
//  "labels": {
//   "test1": "xyz",
//   "test": "abc",
//   "a": "abc"
//  }
// }

// For this example, I'm going to add a label "b", delete the label "test1", and update
// the label "test".
CkoJsonObject *json = [[CkoJsonObject alloc] init];
[json UpdateString: @"labels.b" value: @"bbb"];
[json UpdateString: @"labels.test" value: @"abc123"];
[json UpdateNull: @"labels.test1"];

// ---- Step 2
// Send a PATCH equivalent to this curl command

// curl -X PATCH --data-binary @[JSON_FILE_NAME].json \
//     -H "Authorization: Bearer [OAUTH2_TOKEN]" \
//     -H "Content-Type: application/json" \
//     "https://www.googleapis.com/storage/v1/b/[BUCKET_NAME]?fields=labels"

CkoHttp *http = [[CkoHttp alloc] init];
http.AuthToken = [sbToken GetAsString];

[http SetUrlVar: @"bucket_name" value: @"chilkat-ocean"];
NSString *url = @"https://www.googleapis.com/storage/v1/b/{$bucket_name}?fields=labels";
CkoHttpResponse *resp = [http PText: @"PATCH" url: url textData: [json Emit] charset: @"utf-8" contentType: @"application/json" md5: NO gzip: NO];
if (http.LastMethodSuccess == NO) {
    NSLog(@"%@",http.LastErrorText);
    return;
}

int responseCode = [resp.StatusCode intValue];
if (responseCode == 401) {
    NSLog(@"%@",resp.BodyStr);
    NSLog(@"%@",@"If invalid credentials, then it is likely the access token expired.");
    NSLog(@"%@",@"Your app should automatically fetch a new access token and re-try.");

    return;
}

// Note: A 400 response code is likely caused by illegal characters used for a label name and/or value.

NSLog(@"%@%d",@"Response code: ",responseCode);
NSLog(@"%@",@"Response body");
NSLog(@"%@",resp.BodyStr);

// A response code = 200 indicates success, and the response body contains the JSON
// for the new/updated set of labels
// Response code: 200
// Response body
// {
//  "labels": {
//   "test": "abc123",
//   "a": "abc",
//   "b": "bbb"
//  }
// }