trusted-scoring-signals.py

import json

from fledge.tentative.resources import fledge_http_server_util

# Script to generate trusted scoring signals. The responses depends on the

# query strings in the ads Urls - some result in entire response failures,

# others affect only their own value. Each renderUrl potentially has a

# signalsParam, which is a comma-delimited list of instructions that can

# each affect either the value associated with the renderUrl, or the

# response as a whole.

def main(request, response):

    try:

        params = fledge_http_server_util.decode_trusted_scoring_signals_params(request)

    except ValueError as ve:

        return fail(response, str(ve))

    response.status = (200, b"OK")

    # The JSON representation of this is used as the response body.

    responseBody = {"renderUrls": {}}

    # Set when certain special keys are observed, used in place of the JSON

    # representation of `responseBody`, when set.

    body = None

    contentType = "application/json"

    adAuctionAllowed = "true"

    dataVersion = None

    cors = False

    for urlList in params.urlLists:

        for renderUrl in urlList["urls"]:

            value = "default value"

            addValue = True

            try:

                signalsParams = fledge_http_server_util.decode_render_url_signals_params(renderUrl)

            except ValueError as ve:

                return fail(response, str(ve))

            for signalsParam in signalsParams:

                if signalsParam == "close-connection":

                    # Close connection without writing anything, to simulate a

                    # network error. The write call is needed to avoid writing the

                    # default headers.

                    response.writer.write("")

                    response.close_connection = True

                    return

                elif signalsParam.startswith("replace-body:"):

                    # Replace entire response body. Continue to run through other

                    # renderUrls, to allow them to modify request headers.

                    body = signalsParam.split(':', 1)[1]

                elif signalsParam.startswith("data-version:"):

                    dataVersion = signalsParam.split(':', 1)[1]

                elif signalsParam == "http-error":

                    response.status = (404, b"Not found")

                elif signalsParam == "no-content-type":

                    contentType = None

                elif signalsParam == "wrong-content-type":

                    contentType = 'text/plain'

                elif signalsParam == "bad-ad-auction-allowed":

                    adAuctionAllowed = "sometimes"

                elif signalsParam == "ad-auction-not-allowed":

                    adAuctionAllowed = "false"

                elif signalsParam == "no-ad-auction-allow":

                    adAuctionAllowed = None

                elif signalsParam == "wrong-url":

                    renderUrl = "https://wrong-url.test/"

                elif signalsParam == "no-value":

                    addValue = False

                elif signalsParam == "null-value":

                    value = None

                elif signalsParam == "num-value":

                    value = 1

                elif signalsParam == "string-value":

                    value = "1"

                elif signalsParam == "array-value":

                    value = [1, "foo", None]

                elif signalsParam == "object-value":

                    value = {"a":"b", "c":["d"]}

                elif signalsParam == "hostname":

                    value = params.hostname

                elif signalsParam == "headers":

                    value = fledge_http_server_util.headers_to_ascii(request.headers)

                elif signalsParam == "url":

                    value = request.url

                elif signalsParam == "cors":

                    cors = True

            if addValue:

                if urlList["type"] not in responseBody:

                    responseBody[urlList["type"]] = {}

                responseBody[urlList["type"]][renderUrl] = value

    # If the signalsParam embedded inside a render URL calls for CORS, add

    # appropriate response headers, and fully handle preflights.

    if cors and fledge_http_server_util.handle_cors_headers_and_preflight(

            request, response):

        return

    if contentType:

        response.headers.set("Content-Type", contentType)

    if adAuctionAllowed:

        response.headers.set("Ad-Auction-Allowed", adAuctionAllowed)

    if dataVersion:

        response.headers.set("Data-Version", dataVersion)

    if body != None:

        return body

    return json.dumps(responseBody)

def fail(response, body):

    response.status = (400, "Bad Request")

    response.headers.set(b"Content-Type", b"text/plain")

    return body