// Copyright 2008 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following
// disclaimer in the documentation and/or other materials provided
// with the distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#include <v8.h>
#include <string>
#include <map>
using namespace std;
using namespace v8;
// These interfaces represent an existing request processing interface.
// The idea is to imagine a real application that uses these interfaces
// and then add scripting capabilities that allow you to interact with
// the objects through JavaScript.
/**
* A simplified http request.
*/
class HttpRequest {
public:
virtual ~HttpRequest() { }
virtual const string& Path() = 0;
virtual const string& Referrer() = 0;
virtual const string& Host() = 0;
virtual const string& UserAgent() = 0;
};
/**
* The abstract superclass of http request processors.
*/
class HttpRequestProcessor {
public:
virtual ~HttpRequestProcessor() { }
// Initialize this processor. The map contains options that control
// how requests should be processed.
virtual bool Initialize(map<string, string>* options,
map<string, string>* output) = 0;
// Process a single request.
virtual bool Process(HttpRequest* req) = 0;
static void Log(const char* event);
};
/**
* An http request processor that is scriptable using JavaScript.
*/
class JsHttpRequestProcessor : public HttpRequestProcessor {
public:
// Creates a new processor that processes requests by invoking the
// Process function of the JavaScript script given as an argument.
explicit JsHttpRequestProcessor(Handle<String> script) : script_(script) { }
virtual ~JsHttpRequestProcessor();
virtual bool Initialize(map<string, string>* opts,
map<string, string>* output);
virtual bool Process(HttpRequest* req);
private:
// Execute the script associated with this processor and extract the
// Process function. Returns true if this succeeded, otherwise false.
bool ExecuteScript(Handle<String> script);
// Wrap the options and output map in a JavaScript objects and
// install it in the global namespace as 'options' and 'output'.
bool InstallMaps(map<string, string>* opts, map<string, string>* output);
// Constructs the template that describes the JavaScript wrapper
// type for requests.
static Handle<ObjectTemplate> MakeRequestTemplate();
static Handle<ObjectTemplate> MakeMapTemplate();
// Callbacks that access the individual fields of request objects.
static Handle<Value> GetPath(Local<String> name, const AccessorInfo& info);
static Handle<Value> GetReferrer(Local<String> name,
const AccessorInfo& info);
static Handle<Value> GetHost(Local<String> name, const AccessorInfo& info);
static Handle<Value> GetUserAgent(Local<String> name,
const AccessorInfo& info);
// Callbacks that access maps
static Handle<Value> MapGet(Local<String> name, const AccessorInfo& info);
static Handle<Value> MapSet(Local<String> name,
Local<Value> value,
const AccessorInfo& info);
// Utility methods for wrapping C++ objects as JavaScript objects,
// and going back again.
static Handle<Object> WrapMap(map<string, string>* obj);
static map<string, string>* UnwrapMap(Handle<Object> obj);
static Handle<Object> WrapRequest(HttpRequest* obj);
static HttpRequest* UnwrapRequest(Handle<Object> obj);
Handle<String> script_;
Persistent<Context> context_;
Persistent<Function> process_;
static Persistent<ObjectTemplate> request_template_;
static Persistent<ObjectTemplate> map_template_;
};
// -------------------------
// --- P r o c e s s o r ---
// -------------------------
static Handle<Value> LogCallback(const Arguments& args) {
if (args.Length() < 1) return v8::Undefined();
HandleScope scope;
Handle<Value> arg = args[0];
String::Utf8Value value(arg);
HttpRequestProcessor::Log(*value);
return v8::Undefined();
}
// Execute the script and fetch the Process method.
bool JsHttpRequestProcessor::Initialize(map<string, string>* opts,
map<string, string>* output) {
// Create a handle scope to hold the temporary references.
HandleScope handle_scope;
// Create a template for the global object where we set the
// built-in global functions.
Handle<ObjectTemplate> global = ObjectTemplate::New();
global->Set(String::New("log"), FunctionTemplate::New(LogCallback));
// Each processor gets its own context so different processors
// don't affect each other (ignore the first three lines).
Handle<Context> context = Context::New(NULL, global);
// Store the context in the processor object in a persistent handle,
// since we want the reference to remain after we return from this
// method.
context_ = Persistent<Context>::New(context);
// Enter the new context so all the following operations take place
// within it.
Context::Scope context_scope(context);
// Make the options mapping available within the context
if (!InstallMaps(opts, output))
return false;
// Compile and run the script
if (!ExecuteScript(script_))
return false;
// The script compiled and ran correctly. Now we fetch out the
// Process function from the global object.
Handle<String> process_name = String::New("Process");
Handle<Value> process_val = context->Global()->Get(process_name);
// If there is no Process function, or if it is not a function,
// bail out
if (!process_val->IsFunction()) return false;
// It is a function; cast it to a Function
Handle<Function> process_fun = Handle<Function>::Cast(process_val);
// Store the function in a Persistent handle, since we also want
// that to remain after this call returns
process_ = Persistent<Function>::New(process_fun);
// All done; all went well
return true;
}
bool JsHttpRequestProcessor::ExecuteScript(Handle<String> script) {
HandleScope handle_scope;
// We're just about to compile the script; set up an error handler to
// catch any exceptions the script might throw.
TryCatch try_catch;
// Compile the script and check for errors.
Handle<Script> compiled_script = Script::Compile(script);
if (compiled_script.IsEmpty()) {
String::Utf8Value error(try_catch.Exception());
Log(*error);
// The script failed to compile; bail out.
return false;
}
// Run the script!
Handle<Value> result = compiled_script->Run();
if (result.IsEmpty()) {
// The TryCatch above is still in effect and will have caught the error.
String::Utf8Value error(try_catch.Exception());
Log(*error);
// Running the script failed; bail out.
return false;
}
return true;
}
bool JsHttpRequestProcessor::InstallMaps(map<string, string>* opts,
map<string, string>* output) {
HandleScope handle_scope;
// Wrap the map object in a JavaScript wrapper
Handle<Object> opts_obj = WrapMap(opts);
// Set the options object as a property on the global object.
context_->Global()->Set(String::New("options"), opts_obj);
Handle<Object> output_obj = WrapMap(output);
context_->Global()->Set(String::New("output"), output_obj);
return true;
}
bool JsHttpRequestProcessor::Process(HttpRequest* request) {
// Create a handle scope to keep the temporary object references.
HandleScope handle_scope;
// Enter this processor's context so all the remaining operations
// take place there
Context::Scope context_scope(context_);
// Wrap the C++ request object in a JavaScript wrapper
Handle<Object> request_obj = WrapRequest(request);
// Set up an exception handler before calling the Process function
TryCatch try_catch;
// Invoke the process function, giving the global object as 'this'
// and one argument, the request.
const int argc = 1;
Handle<Value> argv[argc] = { request_obj };
Handle<Value> result = process_->Call(context_->Global(), argc, argv);
if (result.IsEmpty()) {
String::Utf8Value error(try_catch.Exception());
Log(*error);
return false;
} else {
return true;
}
}
JsHttpRequestProcessor::~JsHttpRequestProcessor() {
// Dispose the persistent handles. When noone else has any
// references to the objects stored in the handles they will be
// automatically reclaimed.
context_.Dispose();
process_.Dispose();
}
Persistent<ObjectTemplate> JsHttpRequestProcessor::request_template_;
Persistent<ObjectTemplate> JsHttpRequestProcessor::map_template_;
// -----------------------------------
// --- A c c e s s i n g M a p s ---
// -----------------------------------
// Utility function that wraps a C++ http request object in a
// JavaScript object.
Handle<Object> JsHttpRequestProcessor::WrapMap(map<string, string>* obj) {
// Handle scope for temporary handles.
HandleScope handle_scope;
// Fetch the template for creating JavaScript map wrappers.
// It only has to be created once, which we do on demand.
if (request_template_.IsEmpty()) {
Handle<ObjectTemplate> raw_template = MakeMapTemplate();
map_template_ = Persistent<ObjectTemplate>::New(raw_template);
}
Handle<ObjectTemplate> templ = map_template_;
// Create an empty map wrapper.
Handle<Object> result = templ->NewInstance();
// Wrap the raw C++ pointer in an External so it can be referenced
// from within JavaScript.
Handle<External> map_ptr = External::New(obj);
// Store the map pointer in the JavaScript wrapper.
result->SetInternalField(0, map_ptr);
// Return the result through the current handle scope. Since each
// of these handles will go away when the handle scope is deleted
// we need to call Close to let one, the result, escape into the
// outer handle scope.
return handle_scope.Close(result);
}
// Utility function that extracts the C++ map pointer from a wrapper
// object.
map<string, string>* JsHttpRequestProcessor::UnwrapMap(Handle<Object> obj) {
Handle<External> field = Handle<External>::Cast(obj->GetInternalField(0));
void* ptr = field->Value();
return static_cast<map<string, string>*>(ptr);
}
// Convert a JavaScript string to a std::string. To not bother too
// much with string encodings we just use ascii.
string ObjectToString(Local<Value> value) {
String::Utf8Value utf8_value(value);
return string(*utf8_value);
}
Handle<Value> JsHttpRequestProcessor::MapGet(Local<String> name,
const AccessorInfo& info) {
// Fetch the map wrapped by this object.
map<string, string>* obj = UnwrapMap(info.Holder());
// Convert the JavaScript string to a std::string.
string key = ObjectToString(name);
// Look up the value if it exists using the standard STL ideom.
map<string, string>::iterator iter = obj->find(key);
// If the key is not present return an empty handle as signal
if (iter == obj->end()) return Handle<Value>();
// Otherwise fetch the value and wrap it in a JavaScript string
const string& value = (*iter).second;
return String::New(value.c_str(), value.length());
}
Handle<Value> JsHttpRequestProcessor::MapSet(Local<String> name,
Local<Value> value_obj,
const AccessorInfo& info) {
// Fetch the map wrapped by this object.
map<string, string>* obj = UnwrapMap(info.Holder());
// Convert the key and value to std::strings.
string key = ObjectToString(name);
string value = ObjectToString(value_obj);
// Update the map.
(*obj)[key] = value;
// Return the value; any non-empty handle will work.
return value_obj;
}
Handle<ObjectTemplate> JsHttpRequestProcessor::MakeMapTemplate() {
HandleScope handle_scope;
Handle<ObjectTemplate> result = ObjectTemplate::New();
result->SetInternalFieldCount(1);
result->SetNamedPropertyHandler(MapGet, MapSet);
// Again, return the result through the current handle scope.
return handle_scope.Close(result);
}
// -------------------------------------------
// --- A c c e s s i n g R e q u e s t s ---
// -------------------------------------------
/**
* Utility function that wraps a C++ http request object in a
* JavaScript object.
*/
Handle<Object> JsHttpRequestProcessor::WrapRequest(HttpRequest* request) {
// Handle scope for temporary handles.
HandleScope handle_scope;
// Fetch the template for creating JavaScript http request wrappers.
// It only has to be created once, which we do on demand.
if (request_template_.IsEmpty()) {
Handle<ObjectTemplate> raw_template = MakeRequestTemplate();
request_template_ = Persistent<ObjectTemplate>::New(raw_template);
}
Handle<ObjectTemplate> templ = request_template_;
// Create an empty http request wrapper.
Handle<Object> result = templ->NewInstance();
// Wrap the raw C++ pointer in an External so it can be referenced
// from within JavaScript.
Handle<External> request_ptr = External::New(request);
// Store the request pointer in the JavaScript wrapper.
result->SetInternalField(0, request_ptr);
// Return the result through the current handle scope. Since each
// of these handles will go away when the handle scope is deleted
// we need to call Close to let one, the result, escape into the
// outer handle scope.
return handle_scope.Close(result);
}
/**
* Utility function that extracts the C++ http request object from a
* wrapper object.
*/
HttpRequest* JsHttpRequestProcessor::UnwrapRequest(Handle<Object> obj) {
Handle<External> field = Handle<External>::Cast(obj->GetInternalField(0));
void* ptr = field->Value();
return static_cast<HttpRequest*>(ptr);
}
Handle<Value> JsHttpRequestProcessor::GetPath(Local<String> name,
const AccessorInfo& info) {
// Extract the C++ request object from the JavaScript wrapper.
HttpRequest* request = UnwrapRequest(info.Holder());
// Fetch the path.
const string& path = request->Path();
// Wrap the result in a JavaScript string and return it.
return String::New(path.c_str(), path.length());
}
Handle<Value> JsHttpRequestProcessor::GetReferrer(Local<String> name,
const AccessorInfo& info) {
HttpRequest* request = UnwrapRequest(info.Holder());
const string& path = request->Referrer();
return String::New(path.c_str(), path.length());
}
Handle<Value> JsHttpRequestProcessor::GetHost(Local<String> name,
const AccessorInfo& info) {
HttpRequest* request = UnwrapRequest(info.Holder());
const string& path = request->Host();
return String::New(path.c_str(), path.length());
}
Handle<Value> JsHttpRequestProcessor::GetUserAgent(Local<String> name,
const AccessorInfo& info) {
HttpRequest* request = UnwrapRequest(info.Holder());
const string& path = request->UserAgent();
return String::New(path.c_str(), path.length());
}
Handle<ObjectTemplate> JsHttpRequestProcessor::MakeRequestTemplate() {
HandleScope handle_scope;
Handle<ObjectTemplate> result = ObjectTemplate::New();
result->SetInternalFieldCount(1);
// Add accessors for each of the fields of the request.
result->SetAccessor(String::NewSymbol("path"), GetPath);
result->SetAccessor(String::NewSymbol("referrer"), GetReferrer);
result->SetAccessor(String::NewSymbol("host"), GetHost);
result->SetAccessor(String::NewSymbol("userAgent"), GetUserAgent);
// Again, return the result through the current handle scope.
return handle_scope.Close(result);
}
// --- Test ---
void HttpRequestProcessor::Log(const char* event) {
printf("Logged: %s\n", event);
}
/**
* A simplified http request.
*/
class StringHttpRequest : public HttpRequest {
public:
StringHttpRequest(const string& path,
const string& referrer,
const string& host,
const string& user_agent);
virtual const string& Path() { return path_; }
virtual const string& Referrer() { return referrer_; }
virtual const string& Host() { return host_; }
virtual const string& UserAgent() { return user_agent_; }
private:
string path_;
string referrer_;
string host_;
string user_agent_;
};
StringHttpRequest::StringHttpRequest(const string& path,
const string& referrer,
const string& host,
const string& user_agent)
: path_(path),
referrer_(referrer),
host_(host),
user_agent_(user_agent) { }
void ParseOptions(int argc,
char* argv[],
map<string, string>& options,
string* file) {
for (int i = 1; i < argc; i++) {
string arg = argv[i];
int index = arg.find('=', 0);
if (index == string::npos) {
*file = arg;
} else {
string key = arg.substr(0, index);
string value = arg.substr(index+1);
options[key] = value;
}
}
}
// Reads a file into a v8 string.
Handle<String> ReadFile(const string& name) {
FILE* file = fopen(name.c_str(), "rb");
if (file == NULL) return Handle<String>();
fseek(file, 0, SEEK_END);
int size = ftell(file);
rewind(file);
char* chars = new char[size + 1];
chars[size] = '\0';
for (int i = 0; i < size;) {
int read = fread(&chars[i], 1, size - i, file);
i += read;
}
fclose(file);
Handle<String> result = String::New(chars, size);
delete[] chars;
return result;
}
const int kSampleSize = 6;
StringHttpRequest kSampleRequests[kSampleSize] = {
StringHttpRequest("/process.cc", "localhost", "google.com", "firefox"),
StringHttpRequest("/", "localhost", "google.net", "firefox"),
StringHttpRequest("/", "localhost", "google.org", "safari"),
StringHttpRequest("/", "localhost", "yahoo.com", "ie"),
StringHttpRequest("/", "localhost", "yahoo.com", "safari"),
StringHttpRequest("/", "localhost", "yahoo.com", "firefox")
};
bool ProcessEntries(HttpRequestProcessor* processor, int count,
StringHttpRequest* reqs) {
for (int i = 0; i < count; i++) {
if (!processor->Process(&reqs[i]))
return false;
}
return true;
}
void PrintMap(map<string, string>* m) {
for (map<string, string>::iterator i = m->begin(); i != m->end(); i++) {
pair<string, string> entry = *i;
printf("%s: %s\n", entry.first.c_str(), entry.second.c_str());
}
}
int main(int argc, char* argv[]) {
map<string, string> options;
string file;
ParseOptions(argc, argv, options, &file);
if (file.empty()) {
fprintf(stderr, "No script was specified.\n");
return 1;
}
HandleScope scope;
Handle<String> source = ReadFile(file);
if (source.IsEmpty()) {
fprintf(stderr, "Error reading '%s'.\n", file.c_str());
return 1;
}
JsHttpRequestProcessor processor(source);
map<string, string> output;
if (!processor.Initialize(&options, &output)) {
fprintf(stderr, "Error initializing processor.\n");
return 1;
}
if (!ProcessEntries(&processor, kSampleSize, kSampleRequests))
return 1;
PrintMap(&output);
}