(Objective-C) Lower-Level REST API Methods (Google Cloud Storage)

The FullRequest* methods, such as FullRequestBinary, FullRequestMultipart, FullRequestNoBody, FullRequestStream, FullRequestString, etc. are high-level REST API methods that both send the request and receive the response. It is often the case that an application needs make a REST call, but with a finer level of control. The Chilkat REST API provides this feature. An application can break a REST call into the following parts:

1. Send the HTTP request. (via the SendReq* methods)
2. Receive the HTTP response header. (ReadResponseHeader)
3. Receive the HTTP response body. (via the ReadRespBody* methods)

This example demonstrates a REST call using SendReqStringBody, ReadResonseHeader, and ReadRespBodyString.

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#import <CkoAuthGoogle.h>
#import <CkoRest.h>
#import <CkoJsonObject.h>
#import <NSString.h>

// This example demonstrates a REST call using SendReqStringBody, ReadResonseHeader, and ReadRespBodyString.
// It will create a bucket in Google Cloud Storage.
BOOL success;

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

CkoAuthGoogle *gAuth = [[CkoAuthGoogle alloc] init];
// Obtain an access token as shown in one of the following examples:
// See Get Access Token using a Service Account JSON Key
// See Get Access Token using a P12 File

CkoRest *rest = [[CkoRest alloc] init];

// Connect using TLS.
BOOL bAutoReconnect = YES;
success = [rest Connect: @"www.googleapis.com" port: [NSNumber numberWithInt: 443] tls: YES autoReconnect: bAutoReconnect];

// Provide the authentication credentials (i.e. the access key)
success = [rest SetAuthGoogle: gAuth];

// Build the JSON request body for creating a bucket.
// The only required property is the "name", but we'll add more
// to make a better example..
CkoJsonObject *jsonReqBody = [[CkoJsonObject alloc] init];
success = [jsonReqBody AddStringAt: [NSNumber numberWithInt: -1] name: @"name" value: @"chilkat-bucket-c"];
success = [jsonReqBody AddStringAt: [NSNumber numberWithInt: -1] name: @"kind" value: @"storage#bucket"];
success = [jsonReqBody AddStringAt: [NSNumber numberWithInt: -1] name: @"location" value: @"US"];
success = [jsonReqBody AddObjectAt: [NSNumber numberWithInt: -1] name: @"versioning"];

CkoJsonObject *pObjVersioning = [jsonReqBody ObjectOf: @"versioning"];
success = [pObjVersioning AddBoolAt: [NSNumber numberWithInt: -1] name: @"enabled" value: YES];

// Show the HTTP request body we'll be sending.
NSLog(@"%@",[jsonReqBody Emit]);

// Add the required query parameter.
// See https://cloud.google.com/storage/docs/json_api/v1/buckets/insert
success = [rest AddQueryParam: @"project" value: @"chilkattest-1050"];

// Add the Content-Type HTTP request header.
success = [rest AddHeader: @"Content-Type" value: @"application/json; charset=UTF-8"];

// Send the REST HTTP request.
success = [rest SendReqStringBody: @"POST" uriPath: @"/storage/v1/b" bodyText: [jsonReqBody Emit]];
if (success != YES) {
    NSLog(@"%@",rest.LastErrorText);
    return;
}

// Read the response header.
int responseStatusCode = [[rest ReadResponseHeader] intValue];
if (responseStatusCode < 0) {
    // We were unable to receive the response header.
    NSLog(@"%@",rest.LastErrorText);
    return;
}

if (responseStatusCode != 200) {
    // The response was not successful.  We'll still need to receive 
    // the response body, which may contain an error message from the server.
    // If the response has no body, then the method for reading the
    // response body can still be called.  It will simply return with an empty
    // response body.

    // We can examine the response header and status text:
    NSLog(@"%@%@",@"Response status text: ",rest.ResponseStatusText);
    NSLog(@"%@%@",@"Response header: ",rest.ResponseHeader);
}

// Read the response body.  In this case we're expecting it to be JSON..
NSString *responseBodyStr = [rest ReadRespBodyString];
if (rest.LastMethodSuccess != YES) {
    // We were unable to receive the response body.
    // Note: If the response did not include a body (such as for cases where
    // the Content-Length header is 0, or if the response status code implicitly
    // indicates no body, then ReadRespBodyString returns cktrue, and the
    // responseBodyString will be an empty string.
    NSLog(@"%@",rest.LastErrorText);
    return;
}

// Show the JSON response.
NSLog(@"%@%@",@"Json Response: ",responseBodyStr);