(PureBasic) Shopify OAuth2 Authentication

Demonstrates obtaining an access token for a Shopify application using OAuth2 authentication. This example is for non-web-apps, and requires that a browser window be displayed to get authorization from the user.

A web-based application would not obtain an OAuth2 token in this way, because the redirect URL would route back to the web application.

Note: Once an access token is in hand, the remainder of the Chilkat examples, which use an already-obtained access token, apply to both web and non-web apps.

Chilkat PureBasic Module Download Chilkat PureBasic Module

IncludeFile "CkOAuth2.pb"
IncludeFile "CkStringBuilder.pb"

Procedure ChilkatExample()

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

    oauth2.i = CkOAuth2::ckCreate()
    If oauth2.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    success.i

    ; This should be the port in the localhost callback URL for your app.  
    ; The callback URL would look like "http://localhost:3017/" if the port number is 3017.
    ; Make sure that "http://localhost:3017/" is listed in your Whitelisted Redirection URLs for your Shopify app.
    CkOAuth2::setCkListenPort(oauth2, 3017)

    ; The full content of the Authorization Endpoin for Shopify looks like this:
    ; https://{shop}.myshopify.com/admin/oauth/authorize?client_id={api_key}&scope={scopes}&redirect_uri={redirect_uri}&state={nonce}&grant_options[]={option}

    ; Replace "chilkat" with your shop name.
    CkOAuth2::setCkAuthorizationEndpoint(oauth2, "https://chilkat.myshopify.com/admin/oauth/authorize")
    CkOAuth2::setCkTokenEndpoint(oauth2, "https://chilkat.myshopify.com/admin/oauth/access_token")

    ; Replace these with actual values.
    CkOAuth2::setCkClientId(oauth2, "SHOPIFY_API_KEY")
    CkOAuth2::setCkClientSecret(oauth2, "SHOPIFY_API_SECRET_KEY")

    CkOAuth2::setCkCodeChallenge(oauth2, 1)
    CkOAuth2::setCkCodeChallengeMethod(oauth2, "S256")

    ; Set requested scopes.  See https://help.shopify.com/api/getting-started/authentication/oauth
    CkOAuth2::setCkScope(oauth2, "read_product_listings,read_customers,read_orders,read_draft_orders")

    ; Begin the OAuth2 three-legged flow.  This returns a URL that should be loaded in a browser.
    url.s = CkOAuth2::ckStartAuth(oauth2)
    If CkOAuth2::ckLastMethodSuccess(oauth2) <> 1
        Debug CkOAuth2::ckLastErrorText(oauth2)
        CkOAuth2::ckDispose(oauth2)
        ProcedureReturn
    EndIf

    Debug "url: " + url

    ; At this point, your application should load the URL in a browser.
    ; For example, 
    ; in C#: System.Diagnostics.Process.Start(url);
    ; in Java: Desktop.getDesktop().browse(new URI(url));
    ; in VBScript: Set wsh=WScript.CreateObject("WScript.Shell")
    ;              wsh.Run url
    ; in Xojo: ShowURL(url)  (see http://docs.xojo.com/index.php/ShowURL)
    ; in Dataflex: Runprogram Background "c:\Program Files\Internet Explorer\iexplore.exe" sUrl        
    ; The Google account owner would interactively accept or deny the authorization request.

    ; Add the code to load the url in a web browser here...
    ; Add the code to load the url in a web browser here...
    ; Add the code to load the url in a web browser here...
    ; System.Diagnostics.Process.Start(url);

    ; Now wait for the authorization.
    ; We'll wait for a max of 30 seconds.
    numMsWaited.i = 0
    While (numMsWaited < 30000) AND (CkOAuth2::ckAuthFlowState(oauth2) < 3)
        CkOAuth2::ckSleepMs(oauth2,100)
        numMsWaited = numMsWaited + 100
    Wend

    ; If there was no response from the browser within 30 seconds, then 
    ; the AuthFlowState will be equal to 1 or 2.
    ; 1: Waiting for Redirect. The OAuth2 background thread is waiting to receive the redirect HTTP request from the browser.
    ; 2: Waiting for Final Response. The OAuth2 background thread is waiting for the final access token response.
    ; In that case, cancel the background task started in the call to StartAuth.
    If CkOAuth2::ckAuthFlowState(oauth2) < 3
        CkOAuth2::ckCancel(oauth2)
        Debug "No response from the browser!"
        CkOAuth2::ckDispose(oauth2)
        ProcedureReturn
    EndIf

    ; Check the AuthFlowState to see if authorization was granted, denied, or if some error occurred
    ; The possible AuthFlowState values are:
    ; 3: Completed with Success. The OAuth2 flow has completed, the background thread exited, and the successful JSON response is available in AccessTokenResponse property.
    ; 4: Completed with Access Denied. The OAuth2 flow has completed, the background thread exited, and the error JSON is available in AccessTokenResponse property.
    ; 5: Failed Prior to Completion. The OAuth2 flow failed to complete, the background thread exited, and the error information is available in the FailureInfo property.
    If CkOAuth2::ckAuthFlowState(oauth2) = 5
        Debug "OAuth2 failed to complete."
        Debug CkOAuth2::ckFailureInfo(oauth2)
        CkOAuth2::ckDispose(oauth2)
        ProcedureReturn
    EndIf

    If CkOAuth2::ckAuthFlowState(oauth2) = 4
        Debug "OAuth2 authorization was denied."
        Debug CkOAuth2::ckAccessTokenResponse(oauth2)
        CkOAuth2::ckDispose(oauth2)
        ProcedureReturn
    EndIf

    If CkOAuth2::ckAuthFlowState(oauth2) <> 3
        Debug "Unexpected AuthFlowState:" + Str(CkOAuth2::ckAuthFlowState(oauth2))
        CkOAuth2::ckDispose(oauth2)
        ProcedureReturn
    EndIf

    Debug "OAuth2 authorization granted!"
    Debug "Access Token = " + CkOAuth2::ckAccessToken(oauth2)

    ; Save the full JSON access token response to a file.
    sbJson.i = CkStringBuilder::ckCreate()
    If sbJson.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    CkStringBuilder::ckAppend(sbJson,CkOAuth2::ckAccessTokenResponse(oauth2))
    CkStringBuilder::ckWriteFile(sbJson,"qa_data/tokens/shopify-access-token.json","utf-8",0)

    ; The saved JSON response looks like this:

    ; {
    ;   "access_token": "1364e43a5332583188cb27bc85469b1f",
    ;   "scope": "read_product_listings,read_customers,read_orders,read_draft_orders"
    ; }


    CkOAuth2::ckDispose(oauth2)
    CkStringBuilder::ckDispose(sbJson)


    ProcedureReturn
EndProcedure