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// Copyright 2023 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "chrome/browser/printing/web_api/web_printing_service_binder.h"
#include <utility>
#include "base/feature_list.h"
#include "content/public/browser/isolated_context_util.h"
#include "content/public/browser/render_frame_host.h"
#include "printing/buildflags/buildflags.h"
#include "services/network/public/mojom/permissions_policy/permissions_policy_feature.mojom.h"
#include "third_party/blink/public/common/features_generated.h"
#if BUILDFLAG(IS_CHROMEOS) && BUILDFLAG(USE_CUPS)
#include "chrome/browser/printing/web_api/web_printing_service_chromeos.h"
#include "chrome/browser/web_applications/web_app_tab_helper.h"
#include "content/public/browser/web_contents.h"
#include "extensions/browser/extension_registry.h"
#endif
namespace printing {
#if BUILDFLAG(IS_CHROMEOS) && BUILDFLAG(USE_CUPS)
std::optional<std::string> InferAssociatedAppId(
content::RenderFrameHost* render_frame_host) {
if (auto* web_app_id = web_app::WebAppTabHelper::GetAppId(
content::WebContents::FromRenderFrameHost(render_frame_host))) {
// If this is a web app, return its id.
return *web_app_id;
}
auto* extension =
extensions::ExtensionRegistry::Get(render_frame_host->GetBrowserContext())
->enabled_extensions()
.GetExtensionOrAppByURL(render_frame_host->GetLastCommittedURL());
if (extension && extension->is_platform_app()) {
// If this is a chrome app, return its id.
return extension->id();
}
return std::nullopt;
}
#endif
void CreateWebPrintingServiceForFrame(
content::RenderFrameHost* render_frame_host,
mojo::PendingReceiver<blink::mojom::WebPrintingService> receiver) {
if (!base::FeatureList::IsEnabled(blink::features::kWebPrinting)) {
mojo::ReportBadMessage("The WebPrinting API is disabled.");
return;
}
if (!render_frame_host->IsFeatureEnabled(
network::mojom::PermissionsPolicyFeature::kWebPrinting)) {
mojo::ReportBadMessage(
"Access to the feature \"web-printing\" is disallowed by permissions "
"policy.");
return;
}
// There are some security concerns around this API's fingerprinting surface
// and the lack of motivating use cases outside of IWAs -- most users either
// have no printers at all or only one which leads us to a 'take it or leave
// it' situation where regular websites do not really need to access printer
// information.
// This decision might be reconsidered in the future, but for now we'll stick
// to the IWA-only approach.
if (!content::HasIsolatedContextCapability(render_frame_host)) {
mojo::ReportBadMessage(
"Frame is not sufficiently isolated to use the WebPrinting API.");
return;
}
#if BUILDFLAG(IS_CHROMEOS) && BUILDFLAG(USE_CUPS)
std::optional<std::string> app_id = InferAssociatedAppId(render_frame_host);
if (!app_id) {
mojo::ReportBadMessage("Web Printing API is only available inside apps.");
return;
}
// This class inherits from content::DocumentService<> -- its lifetime is
// bound to the associated `render_frame_host`.
new WebPrintingServiceChromeOS(render_frame_host, std::move(receiver),
*app_id);
#else
mojo::ReportBadMessage(
"WebPrinting API is currently supported only on ChromeOS with CUPS "
"enabled.");
#endif
}
} // namespace printing
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