Sample code for 30+ languages & platforms
DataFlex

USPS OAuth2 Client Credentials

See more OAuth2 Examples

Get an OAuth2 access token for the United States Postal Service (USPS) REST API.

Chilkat DataFlex Downloads

DataFlex
Use ChilkatAx-win32.pkg

Procedure Test
    Boolean iSuccess
    Handle hoHttp
    Variant vReq
    Handle hoReq
    Variant vResp
    Handle hoResp
    Variant vSbResponseBody
    Handle hoSbResponseBody
    Handle hoJResp
    Integer iRespStatusCode
    String sAccess_token
    String sToken_type
    Integer iIssued_at
    Integer iExpires_in
    String sStatus
    String sScope
    String sIssuer
    String sClient_id
    String sApplication_name
    String sApi_products
    String sPublic_key
    String sTemp1

    Move False To iSuccess

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

    Get Create (RefClass(cComChilkatHttp)) To hoHttp
    If (Not(IsComObjectCreated(hoHttp))) Begin
        Send CreateComObject of hoHttp
    End

    // Implements the following CURL command:

    // curl -X POST https://apis.usps.com/oauth2/v3/token \
    //   -H "Content-Type: application/x-www-form-urlencoded" \
    //   -d "grant_type=client_credentials" \
    //   -d "client_id=123456789" \
    //   -d "client_secret=A1B2C3D4E5" \
    //   -d "scope=ResourceA+ResourceB+ResourceC"

    // Use the following online tool to generate HTTP code from a CURL command
    // Convert a cURL Command to HTTP Source Code

    Get Create (RefClass(cComChilkatHttpRequest)) To hoReq
    If (Not(IsComObjectCreated(hoReq))) Begin
        Send CreateComObject of hoReq
    End
    Send ComAddParam To hoReq "grant_type" "client_credentials"
    Send ComAddParam To hoReq "client_id" "123456789"
    Send ComAddParam To hoReq "client_secret" "A1B2C3D4E5"
    Send ComAddParam To hoReq "scope" "ResourceA+ResourceB+ResourceC"

    Set ComHttpVerb Of hoReq To "POST"
    Set ComContentType Of hoReq To "application/x-www-form-urlencoded"

    Get Create (RefClass(cComChilkatHttpResponse)) To hoResp
    If (Not(IsComObjectCreated(hoResp))) Begin
        Send CreateComObject of hoResp
    End
    Get pvComObject of hoReq to vReq
    Get pvComObject of hoResp to vResp
    Get ComHttpReq Of hoHttp "https://apis.usps.com/oauth2/v3/token" vReq vResp To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoHttp To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Get Create (RefClass(cComChilkatStringBuilder)) To hoSbResponseBody
    If (Not(IsComObjectCreated(hoSbResponseBody))) Begin
        Send CreateComObject of hoSbResponseBody
    End
    Get pvComObject of hoSbResponseBody to vSbResponseBody
    Get ComGetBodySb Of hoResp vSbResponseBody To iSuccess

    Get Create (RefClass(cComChilkatJsonObject)) To hoJResp
    If (Not(IsComObjectCreated(hoJResp))) Begin
        Send CreateComObject of hoJResp
    End
    Get pvComObject of hoSbResponseBody to vSbResponseBody
    Get ComLoadSb Of hoJResp vSbResponseBody To iSuccess
    Set ComEmitCompact Of hoJResp To False

    Showln "Response Body:"
    Get ComEmit Of hoJResp To sTemp1
    Showln sTemp1

    Get ComStatusCode Of hoResp To iRespStatusCode
    Showln "Response Status Code = " iRespStatusCode
    If (iRespStatusCode >= 400) Begin
        Showln "Response Header:"
        Get ComHeader Of hoResp To sTemp1
        Showln sTemp1
        Showln "Failed."
        Procedure_Return
    End

    // Sample JSON response:
    // (Sample code for parsing the JSON response is shown below)

    // {
    //   "access_token": "eyJraWQiOiIxMDEwMTAiLCJ0eXAiOiJKV1QiLCJhbGciOiJSUzI1NiJ9.eyJzdWIiOiIiLCJhdWQiOiJhZGRyZXNzZXMgaW50ZXJuYXRpb25hbC1wcmljZXMgc3Vic2NyaXB0aW9ucyBwYXltZW50cyBwaWNrdXAgdHJhY2tpbmcgbGFiZWxzIHNjYW4tZm9ybXMgY29tcGFuaWVzIHNlcnZpY2UtZGVsaXZlcnktc3RhbmRhcmRzIGxvY2F0aW9ucyBpbnRlcm5hdGlvbmFsLWxhYmVscyBwcmljZXMiLCJhenAiOiJoeXI3YjN2Q1J0cFl0QUhNMWE4Y2RVcmt5eUZtTmtiZyIsIm9yZ2FuaXphdGlvbl9pZCI6IjAiLCJpc3MiOiJ1cm46XC9cL2FwaS51c3BzLmNvbSIsImV4cCI6MTY4MDkxNzc4NiwiaWF0IjoxNjgwODg4OTg2LCJqdGkiOiI3YjU5MzJlMS05NjIxLTQzZDAtYTMyNy0xMzIxYWVjNzJjZGYifQ.QzrUxlT2rG4jvYbMDGnk23j8ZYfHJcdXPKR9CbSmcKeVpURaHhEMpPB6K4x5ut3xxeEGSzeE5VRz8vixI4iqyHsD8rSdkLTPHy0iovUHOZQBAJVQ6hii9jpLhxUXmiTtH3jKzSj_f2fuNmZbIGhf-CR2FBeWF-aBPzEDEMV95nkCUMfW_Z2BmkbraSfvQZxkCO-cLrMAwlYcrzUtaJ7vnazeQB4sep5BBHBEvsa4kfq6_tz6BAKgv3R7cI2NkSv-wgy_IGoTjVCMTS8mJHGs_t8cWCO8-z4lxW1tUwIBKOCUDpmEEnGgiG6Sl0C_gGl4bZ5cDSl4IgPpcOVi9jZ7LA",
    //   "token_type": "Bearer",
    //   "issued_at": 1680888985929,
    //   "expires_in": 28799,
    //   "status": "approved",
    //   "scope": "addresses international-prices subscriptions payments pickup tracking labels scan-forms companies service-delivery-standards locations international-labels prices",
    //   "issuer": "api.usps.com",
    //   "client_id": "hyr7b3vCRtpYtAHM1a8cdUrkyyFmNkbg",
    //   "application_name": "Silver Shipper Developer",
    //   "api_products": "[Shipping-Silver]",
    //   "public_key": "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"
    // }

    // Sample code for parsing the JSON response...
    // Use the following online tool to generate parsing code from sample JSON:
    // Generate Parsing Code from JSON

    Get ComStringOf Of hoJResp "access_token" To sAccess_token
    Get ComStringOf Of hoJResp "token_type" To sToken_type
    Get ComIntOf Of hoJResp "issued_at" To iIssued_at
    Get ComIntOf Of hoJResp "expires_in" To iExpires_in
    Get ComStringOf Of hoJResp "status" To sStatus
    Get ComStringOf Of hoJResp "scope" To sScope
    Get ComStringOf Of hoJResp "issuer" To sIssuer
    Get ComStringOf Of hoJResp "client_id" To sClient_id
    Get ComStringOf Of hoJResp "application_name" To sApplication_name
    Get ComStringOf Of hoJResp "api_products" To sApi_products
    Get ComStringOf Of hoJResp "public_key" To sPublic_key


End_Procedure