(Tcl) Dropbox: OAuth2 Authorization to Obtain an Access Token

Demonstrates how to get a Dropbox OAuth2 access token from a desktop application or script.

This example runs the OAuth 2.0 authorization flow that lets the user sign in to Dropbox and authorize your app.

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load ./chilkat.dll

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

# Note: This example requires Chilkat v9.5.0.66 or greater to work properly.

set oauth2 [new_CkOAuth2]

# The port should match the Authorized Redirect URL in your Dropbox app, 
# which would look like "http://localhost:3017/"
CkOAuth2_put_ListenPort $oauth2 3017

# IMPORTANT: One of the OAuth2 redirect URIs for your Dropbox app must be
# exactly this string:  http://localhost:3017/

CkOAuth2_put_AuthorizationEndpoint $oauth2 "https://www.dropbox.com/oauth2/authorize"
CkOAuth2_put_TokenEndpoint $oauth2 "https://api.dropboxapi.com/oauth2/token"

# Replace these with actual values.
CkOAuth2_put_ClientId $oauth2 "DROPBOX_APP_KEY"
CkOAuth2_put_ClientSecret $oauth2 "DROPBOX_APP_SECRET"
CkOAuth2_put_CodeChallenge $oauth2 0

# Add token_access_type=offline to also get a refresh token in the response
CkOAuth2_AddAuthQueryParam $oauth2 "token_access_type" "offline"

# Begin the OAuth2 three-legged flow.  This returns a URL that should be loaded in a browser.
set url [CkOAuth2_startAuth $oauth2]
if {[CkOAuth2_get_LastMethodSuccess $oauth2] != 1} then {
    puts [CkOAuth2_lastErrorText $oauth2]
    delete_CkOAuth2 $oauth2
    exit
}

# 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 Microsoft 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...

# Now wait for the authorization.
# We'll wait for a max of 30 seconds.
set numMsWaited 0
while {expr [$numMsWaited < 30000]  &&  [[CkOAuth2_get_AuthFlowState $oauth2] < 3]} {
    CkOAuth2_SleepMs $oauth2 100
    set numMsWaited [expr $numMsWaited + 100]
}

# 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_get_AuthFlowState $oauth2] < 3} then {
    CkOAuth2_Cancel $oauth2
    puts "No response from the browser!"
    delete_CkOAuth2 $oauth2
    exit
}

# 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_get_AuthFlowState $oauth2] == 5} then {
    puts "OAuth2 failed to complete."
    puts [CkOAuth2_failureInfo $oauth2]
    delete_CkOAuth2 $oauth2
    exit
}

if {[CkOAuth2_get_AuthFlowState $oauth2] == 4} then {
    puts "OAuth2 authorization was denied."
    puts [CkOAuth2_accessTokenResponse $oauth2]
    delete_CkOAuth2 $oauth2
    exit
}

if {[CkOAuth2_get_AuthFlowState $oauth2] != 3} then {
    puts "Unexpected AuthFlowState:[CkOAuth2_get_AuthFlowState $oauth2]"
    delete_CkOAuth2 $oauth2
    exit
}

puts "OAuth2 authorization granted!"

set json [new_CkJsonObject]

CkJsonObject_Load $json [CkOAuth2_accessTokenResponse $oauth2]
CkJsonObject_put_EmitCompact $json 0

puts "Access Token Response = [CkJsonObject_emit $json]"

# A sample access token response:

# {
#   "access_token": "...",
#   "token_type": "bearer",
#   "expires_in": 14399,
#   "refresh_token": "...",
#   "scope": "account_info.read",
#   "uid": "562542581",
#   "account_id": "dbid:AACQhDS0E3_Vb72Ynd0F-GxGWdTI2qcTHzA"
# }

puts "Access Token = [CkOAuth2_accessToken $oauth2]"

# Save the JSON access token response to a file for subsequent use..
CkJsonObject_WriteFile $json "qa_data/tokens/dropbox.json"

delete_CkOAuth2 $oauth2
delete_CkJsonObject $json