Tcl Requires Chilkat v11.0.0+

Lower-Level REST API Methods (Google Cloud Storage)

See more REST Examples

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.

Tcl

load ./chilkat.dll

set success 0

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

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

set gAuth [new_CkAuthGoogle]

#  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

set rest [new_CkRest]

#  Connect using TLS.
set bAutoReconnect 1
set success [CkRest_Connect $rest "www.googleapis.com" 443 1 $bAutoReconnect]

#  Provide the authentication credentials (i.e. the access key)
set success [CkRest_SetAuthGoogle $rest $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..
set jsonReqBody [new_CkJsonObject]

set success [CkJsonObject_AddStringAt $jsonReqBody -1 "name" "chilkat-bucket-c"]
set success [CkJsonObject_AddStringAt $jsonReqBody -1 "kind" "storage#bucket"]
set success [CkJsonObject_AddStringAt $jsonReqBody -1 "location" "US"]

set objVersioning [new_CkJsonObject]

CkJsonObject_AppendObject2 $jsonReqBody "versioning" $objVersioning
set success [CkJsonObject_AddBoolAt $objVersioning -1 "enabled" 1]

#  Show the HTTP request body we'll be sending.
puts [CkJsonObject_emit $jsonReqBody]

#  Add the required query parameter.
#  See https://cloud.google.com/storage/docs/json_api/v1/buckets/insert
set success [CkRest_AddQueryParam $rest "project" "chilkattest-1050"]

#  Add the Content-Type HTTP request header.
set success [CkRest_AddHeader $rest "Content-Type" "application/json; charset=UTF-8"]

#  Send the REST HTTP request.
set success [CkRest_SendReqStringBody $rest "POST" "/storage/v1/b" [CkJsonObject_emit $jsonReqBody]]
if {$success == 0} then {
    puts [CkRest_lastErrorText $rest]
    delete_CkAuthGoogle $gAuth
    delete_CkRest $rest
    delete_CkJsonObject $jsonReqBody
    delete_CkJsonObject $objVersioning
    exit
}

#  Read the response header.
set responseStatusCode [CkRest_ReadResponseHeader $rest]
if {$responseStatusCode < 0} then {
    #  We were unable to receive the response header.
    puts [CkRest_lastErrorText $rest]
    delete_CkAuthGoogle $gAuth
    delete_CkRest $rest
    delete_CkJsonObject $jsonReqBody
    delete_CkJsonObject $objVersioning
    exit
}

if {$responseStatusCode != 200} then {
    #  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:
    puts "Response status text: [CkRest_responseStatusText $rest]"
    puts "Response header: [CkRest_responseHeader $rest]"
}

#  Read the response body.  In this case we're expecting it to be JSON..
set responseBodyStr [CkRest_readRespBodyString $rest]
if {[CkRest_get_LastMethodSuccess $rest] != 1} then {
    #  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.
    puts [CkRest_lastErrorText $rest]
    delete_CkAuthGoogle $gAuth
    delete_CkRest $rest
    delete_CkJsonObject $jsonReqBody
    delete_CkJsonObject $objVersioning
    exit
}

#  Show the JSON response.
puts "Json Response: $responseBodyStr"

delete_CkAuthGoogle $gAuth
delete_CkRest $rest
delete_CkJsonObject $jsonReqBody
delete_CkJsonObject $objVersioning