When compiling the following beautiful piece of code ...
#JS()
library nodejs;
import 'package:js/js.dart';
#JS()
class Exports {
external set functionName(Function function);
}
#JS()
external Exports get exports;
void _someDartFunction(dynamic s) {
print('Hello from Dirt!');
}
void main(List<String> arguments) {
exports.functionName = allowInterop(_someDartFunction);
}
... from dart to js using the dart2js command like this:
dart2js -o node_modules/nodejs/index.js bin/main.dart
The nodule is called 'nodejs' (the name is not a problem in this context!). The module is initialised before by npm with an appropriate package.json.
Then I start nodejs and require the module
$ nodejs
> var n = require("nodejs")
ReferenceError: self is not defined
at Object.main (/home/buergerling/Schreibtisch/dart/nodejs1/node_modules/njs/index.js:2544:28)
at /home/buergerling/Schreibtisch/dart/nodejs1/node_modules/njs/index.js:3569:9
at init.currentScript (/home/buergerling/Schreibtisch/dart/nodejs1/node_modules/njs/index.js:3549:7)
at dartProgram (/home/buergerling/Schreibtisch/dart/nodejs1/node_modules/njs/index.js:3564:5)
getting an error. This problem can be solve be cancelling self from the compiled index.js file.
The problem can be spotted here:
...
main: function($arguments) {
var t1 = type$.Function;
J.set$functionName$x(self.exports, P.allowInterop(D.main___someDartFunction$closure(), t1));
J.set$functionName$x(self.module.exports, P.allowInterop(D.main___someDartFunction$closure(), t1));
self.functionName = P.allowInterop(D.main___someDartFunction$closure(), t1);
P.print("Hello from Dirt!");
},
Exports: function Exports() {
}
...
Changing self.exports into exports solves the problem and the module can be loaded and used as expected.
Is there a more elegant solution than editing the compiled file by hand?
Related
I'm trying to get list of top level class declarations with Dart's analysis server. So, I'm sending search.findTopLevelDeclarations request, but search results are always empty.
It seems to me that analysis server don't know where to search. I've tried to set my project's root as execution context (execution.createContext) root and/or analysis root (analysis.setAnalysisRoots), but search results are still empty.
What should I do to make server understand where to search declarations?
Never played with this before so I got into quite a journey...
I don't know how you are interacting with the analysis server but I have made a working example using the analysis_server_client package. One problem doing that is that the version on pub.dev is quite old so I ended up fetching the version from the stable branch of Dart SDK:
https://github.com/dart-lang/sdk/tree/stable/pkg/analysis_server_client
You can then import the package in your pubspec.yaml by doing:
dependencies:
analysis_server_client:
path: /path/to/analysis_server_client
I then made a simplified version of the example code from:
https://github.com/dart-lang/sdk/blob/stable/pkg/analysis_server_client/example/example.dart
import 'dart:io' show exit;
import 'package:analysis_server_client/handler/connection_handler.dart';
import 'package:analysis_server_client/handler/notification_handler.dart';
import 'package:analysis_server_client/protocol.dart';
import 'package:analysis_server_client/server.dart';
final server = Server();
Future<void> main(List<String> args) async {
const targetDirPath = r'C:\tmp\simple_project';
const searchPattern = 'main';
// Launch the server
await server.start();
// Connect to the server
final handler = _Handler(server);
server.listenToOutput(notificationProcessor: handler.handleEvent);
if (!await handler.serverConnected(timeLimit: const Duration(seconds: 15))) {
exit(1);
}
await server.send(ANALYSIS_REQUEST_SET_ANALYSIS_ROOTS,
AnalysisSetAnalysisRootsParams([targetDirPath], const []).toJson());
await server.send(SEARCH_REQUEST_FIND_TOP_LEVEL_DECLARATIONS,
SearchFindTopLevelDeclarationsParams(searchPattern).toJson());
}
class _Handler with NotificationHandler, ConnectionHandler {
#override
final Server server;
_Handler(this.server);
#override
void onSearchResults(SearchResultsParams params) {
print('-- Start of result --');
params.results.forEach(print);
print('-- End of result --');
server.stop();
}
}
The project at C:\tmp\simple_project is a simple project created with the following which means it just contains a single main method:
dart create -t console-simple simple_project
When I run my analyzer program I get the following output:
-- Start of result --
{"location":{"file":"C:\\tmp\\simple_project\\bin\\simple_project.dart","offset":5,"length":4,"startLine":1,"startColumn":6,"endLine":1,"endColumn":10},"kind":"DECLARATION","isPotential":false,"path":[{"kind":"FUNCTION","name":"main","location":{"file":"C:\\tmp\\simple_project\\bin\\simple_project.dart","offset":5,"length":4,"startLine":1,"startColumn":6,"endLine":1,"endColumn":10},"flags":8,"parameters":"(List<String> arguments)","returnType":"void"},{"kind":"COMPILATION_UNIT","name":"simple_project.dart","location":{"file":"C:\\tmp\\simple_project\\bin\\simple_project.dart","offset":0,"length":0,"startLine":1,"startColumn":1,"endLine":1,"endColumn":1},"flags":16},{"kind":"LIBRARY","name":"","location":{"file":"C:\\tmp\\simple_project\\bin\\simple_project.dart","offset":0,"length":0,"startLine":1,"startColumn":1,"endLine":1,"endColumn":1},"flags":0}]}
-- End of result --
If I change searchPattern to an empty String, I gets a long list of top level declarations around the default included Dart SDK libraries. I am sure there are a way to exclude those.
But as far as I can see, the searchPattern is a regular expression tested against the name of each top level declaration and includes the declaration if its name contain any part of the regular expression.
I found the code responsible for the search here:
#override
Future<List<SearchMatch>> searchTopLevelDeclarations(String pattern) async {
var allElements = <Element>{};
var regExp = RegExp(pattern);
var drivers = _drivers.toList();
for (var driver in drivers) {
var elements = await driver.search.topLevelElements(regExp);
allElements.addAll(elements);
}
return allElements.map(SearchMatchImpl.forElement).toList();
}
https://github.com/dart-lang/sdk/blob/1278bd5adb6a857580f137e47bc521976222f7b9/pkg/analysis_server/lib/src/services/search/search_engine_internal.dart#L113-L123
Which calls into:
/// Returns top-level elements with names matching the given [regExp].
Future<List<Element>> topLevelElements(RegExp regExp) async {
List<Element> elements = <Element>[];
void addElement(Element element) {
if (!element.isSynthetic && regExp.hasMatch(element.displayName)) {
elements.add(element);
}
}
List<FileState> knownFiles = _driver.fsState.knownFiles.toList();
for (FileState file in knownFiles) {
var unitResult = await _driver.getUnitElement(file.path);
if (unitResult is UnitElementResult) {
CompilationUnitElement unitElement = unitResult.element;
unitElement.accessors.forEach(addElement);
unitElement.classes.forEach(addElement);
unitElement.enums.forEach(addElement);
unitElement.extensions.forEach(addElement);
unitElement.functions.forEach(addElement);
unitElement.mixins.forEach(addElement);
unitElement.topLevelVariables.forEach(addElement);
unitElement.typeAliases.forEach(addElement);
}
}
return elements;
}
https://github.com/dart-lang/sdk/blob/1278bd5adb6a857580f137e47bc521976222f7b9/pkg/analyzer/lib/src/dart/analysis/search.dart#L166-L192
I'm trying to use an environment variable value in the nestjs/bull module's #Process() decorator, as follows. How should I provide the 'STAGE' variable as part of the job name?
import { Process, Processor } from '#nestjs/bull';
import { Inject } from '#nestjs/common';
import { ConfigService } from '#nestjs/config';
import { Job } from 'bull';
#Processor('main')
export class MqListener {
constructor(
#Inject(ConfigService) private configService: ConfigService<SuperRootConfig>,
) { }
// The reference to configService is not actually allowed here:
#Process(`testjobs:${this.configService.get('STAGE')}`)
handleTestMessage(job: Job) {
console.log("Message received: ", job.data)
}
}
EDITED with answers (below) from Micael and Jay:
Micael Levi answered the initial question: You can't use the NestJS ConfigModule to get your config into a memory variable. However, running dotenv.config() in your bootstrap function will not work either; you get undefined values for the memory variables if you try to access them from within a Method Decorator. To resolve this, Jay McDoniel points out that you have to import the file before you import AppModule. So this works:
// main.ts
import { NestFactory } from '#nestjs/core';
require('dotenv').config()
import { AppModule } from './app.module';
async function bootstrap() {
const app = await NestFactory.create(AppModule);
await app.listen(process.env.PORT || 4500);
}
bootstrap();
You cannot use this on that context due to how decorator evaluation works. At that time, there's no instance created for MqListener class, thus, using this.configService doens't make sense.
You'll need to access process.env. directly. And so will call dotenv (or what lib that read & parses your dot env file) in that file.
Let's say I want to create a global object called Hello and add the function world on that object, so that any other JavaScript library in the browser can simply call it with window.Hello.world();
How do I create such an object in Dart lang and how do I expose it / place it globally / on the window object?
In plain JavaScript, I would be able to write:
window.Hello = {
world: function() {
console.log("Hello World!");
}
}
window.Hello.world();
But how do you do this in Dart?
I work on Dart-JS interop. Here is the cleanest way to do it using the new package:js/js.dart interop.
#JS()
library your_library;
import 'package:js/js.dart';
#anonymous
#JS()
class HelloObject {
external factory HelloObject({Function world});
external world();
}
#JS()
external set Hello(HelloObject v);
#JS()
external HelloObject get Hello;
main() {
Hello = new HelloObject(world: allowInterop(() { print("Hello from dart"); }));
// You can also call this object from Dart as an added bonus.
// For example you could call this from Dart or Js.
/// Hello.world();
}
I am not sure how it will work with objects, but if you want to do that for methods, it's quite simple:
import 'dart:js' as js;
main() {
js.context['methodFromDart'] = doMyStuff;
}
void doMyStuff(String text) => print(text);
And then in you Javascript you are free to do:
methodFromDart("Hello world to Dart!");
You can try to find a way how to do similar things to objects.
I would like to use clang to preprocess objective C files from an iOS app. I looked over the source code and am trying to implement a pre-processor based on the RecursiveASTVisitor class. However, I seem to be running into many issues that I cannot resolve. I developed a preprocessor to add a "Enter" call at the beginning of each method and an "Exit" call at the end. I also added an "Exit" call before each return statement. I am using the following code to do the instrumentation:
class ExampleVisitor : public RecursiveASTVisitor<ExampleVisitor> {
private:
ASTContext *astContext; // used for getting additional AST info
std::string funcName;
public:
explicit ExampleVisitor(CompilerInstance *CI)
: astContext(&(CI->getASTContext())) // initialize private members
{
rewriter.setSourceMgr(astContext->getSourceManager(), astContext->getLangOpts());
}
virtual bool VisitObjCMethodDecl(ObjCMethodDecl *ND) {
funcName = ND->getDeclName().getAsString();
errs() << "Testing function: " << funcName << "\n";
if (ND->hasBody()) {
rewriter.InsertText(ND->getBody()->getSourceRange().getBegin().getLocWithOffset(1), "\nEnter(\""+funcName+"\");\n");
rewriter.InsertText(ND->getBody()->getSourceRange().getEnd(),"Exit(\""+funcName+"\");\n");
}
return true;
}
virtual bool VisitReturnStmt(ReturnStmt *ret) {
rewriter.InsertText(ret->getSourceRange().getBegin(), "\nExit(\""+funcName+"\");\n");
errs() << "** Rewrote ReturnStmt\n";
return true;
}
virtual ~ExampleVisitor() {}
};
class ExampleASTConsumer : public ASTConsumer {
private:
ExampleVisitor *visitor; // doesn't have to be private
public:
// override the constructor in order to pass CI
explicit ExampleASTConsumer(CompilerInstance *CI)
: visitor(new ExampleVisitor(CI)) // initialize the visitor
{ }
// override this to call our ExampleVisitor on the entire source file
virtual void HandleTranslationUnit(ASTContext &Context) {
/* we can use ASTContext to get the TranslationUnitDecl, which is
a single Decl that collectively represents the entire source file */
visitor->TraverseDecl(Context.getTranslationUnitDecl());
}
};
The code compiles. I created a command line executable "instrument". I then used the following command to run this on a simple Objective C program generated by Xcode:
instrument AppDelegate.m --
I run into two problems. First, I get the error: 'UIKit/UIKit.h' file not found. This is one of the includes generated by Xcode. Second, I'm seeing only some of the return statements being processed in the file. Can someone give me some insights into what is happening?
I'm using the 3.7.0 version of llvm.
I am writing a library in Dart and I have static files under the library folder. I want to be able to read those files, but I'm not sure how to retrieve the path to it... there is not __FILE__ or $0 like in some other languages.
Update: It seems that I was not clear enough. Let this help you understand me:
test.dart
import 'foo.dart';
void main() {
print(Foo.getMyPath());
}
foo.dart
library asd;
class Foo {
static Path getMyPath() => new Path('resources/');
}
It gives me the wrong folder location. It gives me the path to test.dart + resources/, but I want the path to foo.dart + resources/.
As mentioned, you can use mirrors. Here's an example using what you wanted to achieve:
test.dart
import 'foo.dart';
void main() {
print(Foo.getMyPath());
}
foo.dart
library asd;
import 'dart:mirrors';
class Foo {
static Path getMyPath() => new Path('${currentMirrorSystem().libraries['asd'].url}/resources/');
}
It should output something like:
/Users/Kai/test/lib/resources/
There will probably be a better way to do this in a future release. I will update the answer when this is the case.
Update: You could also define a private method in the library:
/**
* Returns the path to the root of this library.
*/
_getRootPath() {
var pathString = new Path(currentMirrorSystem().libraries['LIBNAME'].url).directoryPath.toString().replaceFirst('file:///', '');
return pathString;
}
The dart mirrors API (still experimental, and not available on all platforms such as dart2js yet) exposes a url getter on the LibraryMirror. This should give you what you want.
I'm not aware of any other way to get this information on a library.
#import('dart:mirrors');
#import('package:mylib/mylib.dart');
main(){
final urlOfLib = currentMirrorSystem().libraries['myLibraryName'].url;
}
Generally the usual method of accessing resources which are located at a static position with your library is by use using a relative path.
#import('dart:io');
...
var filePath = new Path('resources/cool.txt');
var file = new File.fromPath(filePath);
// And if you really wanted, you can then get the full path
// Note: below is for example only. It is missing various
// integrity checks like error handling.
file.fullPath.then((path_str) {
print(path_str);
});
See addition API information on Path and on File
As an aside.. If you absolutely wanted to get the same type of output as __FILE__ you can do something like the following:
#import('dart:io');
...
var opts = new Options();
var path = new Path(opts.script);
var file = new File.fromPath(path);
file.fullPath().then((path_str) {
print(path_str);
});