(PureBasic) PayPal -- Get an OAuth 2.0 Access Token

Demonstrates how to send a request to get a PayPal OAuth2 access token. Sends an HTTP request equivalent to the following:

curl https://api.sandbox.paypal.com/v1/oauth2/token \
  -H "Accept: application/json" \
  -H "Accept-Language: en_US" \
  -u "Client-Id:Secret" \
  -d "grant_type=client_credentials"

Chilkat PureBasic Module Download Chilkat PureBasic Module

IncludeFile "CkStringBuilder.pb"
IncludeFile "CkRest.pb"
IncludeFile "CkJsonObject.pb"
IncludeFile "CkDateTime.pb"

Procedure ChilkatExample()

    ; Note: Requires Chilkat v9.5.0.64 or greater.

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

    rest.i = CkRest::ckCreate()
    If rest.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    ; Make the initial connection.
    ; A single REST object, once connected, can be used for many PayPal REST API calls.
    ; The auto-reconnect indicates that if the already-established HTTPS connection is closed,
    ; then it will be automatically re-established as needed.
    bAutoReconnect.i = 1
    success.i = CkRest::ckConnect(rest,"api.sandbox.paypal.com",443,1,bAutoReconnect)
    If success <> 1
        Debug CkRest::ckLastErrorText(rest)
        CkRest::ckDispose(rest)
        ProcedureReturn
    EndIf

    ; Duplicate this request:

    ; 	curl https://api.sandbox.paypal.com/v1/oauth2/token \
    ; 	  -H "Accept: application/json" \
    ; 	  -H "Accept-Language: en_US" \
    ; 	  -u "Client-Id:Secret" \
    ; 	  -d "grant_type=client_credentials"

    CkRest::ckAddHeader(rest,"Accept","application/json")
    CkRest::ckAddHeader(rest,"Accept-Language","en_US")

    ; For additional help on where to find  your client ID and API secret, see PayPal Client_ID and API_Secret
    CkRest::ckSetAuthBasic(rest,"PAYPAL_REST_API_CLIENT_ID","PAYPAL_REST_API_SECRET")

    CkRest::ckAddQueryParam(rest,"grant_type","client_credentials")

    responseStr.s = CkRest::ckFullRequestFormUrlEncoded(rest,"POST","/v1/oauth2/token")
    If CkRest::ckLastMethodSuccess(rest) <> 1
        Debug CkRest::ckLastErrorText(rest)
        CkRest::ckDispose(rest)
        ProcedureReturn
    EndIf

    Debug CkRest::ckLastRequestHeader(rest)

    ; A sample response:

    ; 	{
    ; 	  "scope": "https://api.paypal.com/v1/payments/.* https://api.paypal.com/v1/vault/credit-card https://api.paypal.com/v1/vault/credit-card/.*",
    ; 	  "access_token": "EEwJ6tF9x5WCIZDYzyZGaz6Khbw7raYRIBV_WxVvgmsG",
    ; 	  "token_type": "Bearer",
    ; 	  "app_id": "APP-6XR95014BA15863X",
    ; 	  "expires_in": 28800
    ; 	}

    json.i = CkJsonObject::ckCreate()
    If json.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    CkJsonObject::ckLoad(json,responseStr)
    CkJsonObject::setCkEmitCompact(json, 0)

    ; Check the response status code.  A 200 indicates success..
    If CkRest::ckResponseStatusCode(rest) <> 200
        Debug CkJsonObject::ckEmit(json)
        Debug "Failed."
        CkRest::ckDispose(rest)
        CkJsonObject::ckDispose(json)
        ProcedureReturn
    EndIf

    ; Given that the access token expires in approx 8 hours,
    ; let's record the date/time this token was created.
    ; This will allow us to know beforehand if the token
    ; is expired (and we can then fetch a new token).
    dateTime.i = CkDateTime::ckCreate()
    If dateTime.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    bLocalTime.i = 0
    dtNow.i = CkDateTime::ckGetAsUnixTime(dateTime,bLocalTime)
    CkJsonObject::ckAppendInt(json,"tokenCreateTimeUtc",dtNow)

    ; Examine the access token and save to a file.
    Debug "Access Token: " + CkJsonObject::ckStringOf(json,"access_token")
    Debug "Full JSON Response:"
    Debug CkJsonObject::ckEmit(json)

    sbResponse.i = CkStringBuilder::ckCreate()
    If sbResponse.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    CkStringBuilder::ckAppend(sbResponse,CkJsonObject::ckEmit(json))
    bEmitBom.i = 0
    CkStringBuilder::ckWriteFile(sbResponse,"qa_data/tokens/paypal.json","utf-8",bEmitBom)


    CkRest::ckDispose(rest)
    CkJsonObject::ckDispose(json)
    CkDateTime::ckDispose(dateTime)
    CkStringBuilder::ckDispose(sbResponse)


    ProcedureReturn
EndProcedure