Tcl Requires Chilkat v11.0.0+
QuickBooks - Automatically Refresh Access Token with No User Interaction

Demonstrates how to automaticaly refresh an expired access token and retry the request after a 401 authorization error.
Chilkat Tcl Downloads

Tcl

load ./chilkat.dll

set success 0

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

#  Get our previously obtained OAuth2 access token, which should contain JSON like this:
#  {
#    "expires_in": 3600,
#    "x_refresh_token_expires_in": 8726400,
#    "refresh_token": "L011546037639r ... 3vR2DrbOmg0Sdagw",
#    "access_token": "eyJlbmMiOiJBMTI4Q0 ... oETJEMbeggg",
#    "token_type": "bearer"
#  }

set jsonToken [new_CkJsonObject]

set success [CkJsonObject_LoadFile $jsonToken "qa_data/tokens/qb-access-token.json"]

set rest [new_CkRest]

#  Connect using TLS.
#  A single REST object, once connected, can be used for many Quickbooks 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.
set bAutoReconnect 1
set success [CkRest_Connect $rest "sandbox-quickbooks.api.intuit.com" 443 1 $bAutoReconnect]
if {$success == 0} then {
    puts [CkRest_lastErrorText $rest]
    delete_CkJsonObject $jsonToken
    delete_CkRest $rest
    exit
}

set sbAuth [new_CkStringBuilder]

CkStringBuilder_Append $sbAuth "Bearer "
CkStringBuilder_Append $sbAuth [CkJsonObject_stringOf $jsonToken "access_token"]
CkRest_put_Authorization $rest [CkStringBuilder_getAsString $sbAuth]

CkRest_AddHeader $rest "Accept" "application/json"
CkRest_put_AllowHeaderFolding $rest 0

#  The company ID is 123146096291789
#  The employee ID is 58
set responseBody [CkRest_fullRequestNoBody $rest "GET" "/v3/company/123146096291789/employee/58?minorversion=45"]
if {[CkRest_get_LastMethodSuccess $rest] == 0} then {
    puts [CkRest_lastErrorText $rest]
    delete_CkJsonObject $jsonToken
    delete_CkRest $rest
    delete_CkStringBuilder $sbAuth
    exit
}

#  If we get a 401 authorization error, then it's likely because the access token expired.
#  We can automatically refresh it without interaction from the user.
if {[CkRest_get_ResponseStatusCode $rest] == 401} then {

    set oauth2 [new_CkOAuth2]

    CkOAuth2_put_TokenEndpoint $oauth2 "https://oauth.platform.intuit.com/oauth2/v1/tokens/bearer"

    #  Replace these with actual values.
    CkOAuth2_put_ClientId $oauth2 "QUICKBOOKS-CLIENT-ID"
    CkOAuth2_put_ClientSecret $oauth2 "QUICKBOOKS-CLIENT-SECRET"

    #  Get the "refresh_token"
    CkOAuth2_put_RefreshToken $oauth2 [CkJsonObject_stringOf $jsonToken "refresh_token"]

    #  Send the HTTP POST to refresh the access token..
    set success [CkOAuth2_RefreshAccessToken $oauth2]
    if {$success == 0} then {
        puts [CkOAuth2_lastErrorText $oauth2]
        delete_CkJsonObject $jsonToken
        delete_CkRest $rest
        delete_CkStringBuilder $sbAuth
        delete_CkOAuth2 $oauth2
        exit
    }

    puts "New access token: [CkOAuth2_accessToken $oauth2]"

    #  Update the JSON with the new tokens.
    CkJsonObject_UpdateString $jsonToken "access_token" [CkOAuth2_accessToken $oauth2]

    #  Save the new JSON access token response to a file.
    #  The access + refresh tokens contained in this JSON will be needed for the next refresh.
    set sbJson [new_CkStringBuilder]

    CkJsonObject_put_EmitCompact $jsonToken 0
    CkJsonObject_EmitSb $jsonToken $sbJson
    CkStringBuilder_WriteFile $sbJson "qa_data/tokens/qb-access-token.json" "utf-8" 0

    puts "OAuth2 token refreshed!"
    puts "New Access Token = [CkOAuth2_accessToken $oauth2]"

    CkStringBuilder_Clear $sbAuth
    CkStringBuilder_Append $sbAuth "Bearer "
    CkStringBuilder_Append $sbAuth [CkOAuth2_accessToken $oauth2]
    CkRest_put_Authorization $rest [CkStringBuilder_getAsString $sbAuth]

    #  Now retry the request with the refreshed access token...
    set responseBody [CkRest_fullRequestNoBody $rest "GET" "/v3/company/123146096291789/employee/58?minorversion=45"]
    if {[CkRest_get_LastMethodSuccess $rest] == 0} then {
        puts [CkRest_lastErrorText $rest]
        delete_CkJsonObject $jsonToken
        delete_CkRest $rest
        delete_CkStringBuilder $sbAuth
        delete_CkOAuth2 $oauth2
        delete_CkStringBuilder $sbJson
        exit
    }

}

#  We should expect a 200 response if successful.
if {[CkRest_get_ResponseStatusCode $rest] != 200} then {
    puts "Request Header: "
    puts [CkRest_lastRequestHeader $rest]
    puts "----"
    puts "Response StatusCode = [CkRest_get_ResponseStatusCode $rest]"
    puts "Response StatusLine: [CkRest_responseStatusText $rest]"
    puts "Response Header:"
    puts [CkRest_responseHeader $rest]
    puts "$responseBody"
    delete_CkJsonObject $jsonToken
    delete_CkRest $rest
    delete_CkStringBuilder $sbAuth
    delete_CkOAuth2 $oauth2
    delete_CkStringBuilder $sbJson
    exit
}

#  Load the JSON response into a JSON object for parsing.
#  A sample JSON response is shown below.
set json [new_CkJsonObject]

CkJsonObject_Load $json $responseBody

#  These will be used for parsing date/time strings..
set dtime [new_CkDateTime]

set bLocalTime 1

#  Show the JSON.   
CkJsonObject_put_EmitCompact $json 0
puts [CkJsonObject_emit $json]

#  Get some information from the JSON..
puts "Name: [CkJsonObject_stringOf $json Employee.DisplayName]"
puts "Id: [CkJsonObject_stringOf $json Employee.Id]"
puts "City: [CkJsonObject_stringOf $json Employee.PrimaryAddr.City]"
puts "PostalCode: [CkJsonObject_stringOf $json Employee.PrimaryAddr.PostalCode]"

#  Load the CreateTime into a CkDateTime...
CkDateTime_SetFromTimestamp $dtime [CkJsonObject_stringOf $json "Employee.MetaData.CreateTime"]
set dt [new_CkDtObj]

CkDateTime_ToDtObj $dtime $bLocalTime $dt

puts [CkDtObj_get_Month $dt]/[CkDtObj_get_Day $dt]/[CkDtObj_get_Year $dt]  [CkDtObj_get_Hour $dt]:[CkDtObj_get_Minute $dt]

puts "Success."

#  Use this online tool to generate parsing code from sample JSON: 
#  Generate Parsing Code from JSON

#  ------------------------------------------------------
#  The JSON response looks like this:

#  {
#    "Employee": {
#      "SSN": "XXX-XX-XXXX",
#      "PrimaryAddr": {
#        "Id": "116",
#        "Line1": "45 N. Elm Street",
#        "City": "Middlefield",
#        "CountrySubDivisionCode": "CA",
#        "PostalCode": "93242"
#      },
#      "BillableTime": false,
#      "domain": "QBO",
#      "sparse": false,
#      "Id": "98",
#      "SyncToken": "0",
#      "MetaData": {
#        "CreateTime": "2015-07-24T09:34:35-07:00",
#        "LastUpdatedTime": "2015-07-24T09:34:35-07:00"
#      },
#      "GivenName": "Bill",
#      "FamilyName": "Miller",
#      "DisplayName": "Bill Miller",
#      "PrintOnCheckName": "Bill Miller",
#      "Active": true,
#      "PrimaryPhone": {
#        "FreeFormNumber": "234-525-1234"
#      }
#    },
#    "time": "2015-07-24T09:35:54.805-07:00"
#  }

delete_CkJsonObject $jsonToken
delete_CkRest $rest
delete_CkStringBuilder $sbAuth
delete_CkOAuth2 $oauth2
delete_CkStringBuilder $sbJson
delete_CkJsonObject $json
delete_CkDateTime $dtime
delete_CkDtObj $dt