ios/web/public/url_data_source_ios.h

// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef IOS_WEB_PUBLIC_URL_DATA_SOURCE_IOS_H_
#define IOS_WEB_PUBLIC_URL_DATA_SOURCE_IOS_H_

#include <string>

#include "base/callback.h"
#include "base/memory/ref_counted.h"

namespace base {
class MessageLoop;
class RefCountedMemory;
}

namespace net {
class URLRequest;
}

namespace web {
class BrowserState;

// A URLDataSourceIOS is an object that can answer requests for WebUI data
// asynchronously. An implementation of URLDataSourceIOS should handle calls to
// StartDataRequest() by starting its (implementation-specific) asynchronous
// request for the data, then running the callback given in that method to
// notify.
class URLDataSourceIOS {
 public:
  // Adds a URL data source to |browser_state|.
  static void Add(BrowserState* browser_state, URLDataSourceIOS* source);

  virtual ~URLDataSourceIOS() {}

  // The name of this source.
  // E.g., for favicons, this could be "favicon", which results in paths for
  // specific resources like "favicon/34" getting sent to this source. For
  // sources where a scheme is used instead of the hostname as the unique
  // identifier, the suffix "://" must be added to the return value, eg. for a
  // URLDataSourceIOS which would display resources with URLs on the form
  // your-scheme://anything , GetSource() must return "your-scheme://".
  virtual std::string GetSource() const = 0;

  // Used by StartDataRequest so that the child class can return the data when
  // it's available.
  typedef base::Callback<void(scoped_refptr<base::RefCountedMemory>)>
      GotDataCallback;

  // Called by URLDataSourceIOS to request data at |path|. The string parameter
  // is the path of the request. The child class should run |callback| when the
  // data is available or if the request could not be satisfied. This can be
  // called either in this callback or asynchronously with the response.
  virtual void StartDataRequest(const std::string& path,
                                const GotDataCallback& callback) = 0;

  // Return the mimetype that should be sent with this response, or empty
  // string to specify no mime type.
  virtual std::string GetMimeType(const std::string& path) const = 0;

  // The following methods are all called on the IO thread.

  // Returns true if the URLDataSourceIOS should replace an existing
  // URLDataSourceIOS with the same name that has already been registered. The
  // default is true.
  //
  // WARNING: this is invoked on the IO thread.
  //
  // TODO: nuke this and convert all callers to not replace.
  virtual bool ShouldReplaceExistingSource() const;

  // Returns true if responses from this URLDataSourceIOS can be cached.
  virtual bool AllowCaching() const;

  // By default, "object-src 'none';" is added to CSP. Override to change this.
  virtual std::string GetContentSecurityPolicyObjectSrc() const;

  // By default, the "X-Frame-Options: DENY" header is sent. To stop this from
  // happening, return false. It is OK to return false as needed.
  virtual bool ShouldDenyXFrameOptions() const;

  // By default, only chrome: requests are allowed.  Override in specific WebUI
  // data sources to enable for additional schemes or to implement fancier
  // access control.  Typically used in concert with
  // WebClient::GetAdditionalWebUISchemes() to permit additional WebUI scheme
  // support for an embedder.
  virtual bool ShouldServiceRequest(const net::URLRequest* request) const;

  // Called to inform the source that StartDataRequest() will be called soon.
  // Gives the source an opportunity to rewrite |path| to incorporate extra
  // information from the URLRequest prior to serving.
  virtual void WillServiceRequest(const net::URLRequest* request,
                                  std::string* path) const {}
};

}  // namespace web

#endif  // IOS_WEB_PUBLIC_URL_DATA_SOURCE_IOS_H_