I already using the minify argument when building with dart2js.
I looked at the output and I see that the import 'dart:html causes problems in terms of the output file size (2kb .dart file becomes 182kb .js file). For example it imports SVG package though in my code I never touch any <svg> DOM Elements.
I understand that the compiler doesn't know if I'm going to use svg DOM Elements or not. And I understand that the using of var is one of the reasons of that behavior.
But if I will not use any var keywords, the compiler still doesn't have enough 'power' to strip all unused packages and functions.
Is there any directive I can use to forbid the import of certain packages. I mean built-in packages right now. I'm using IntelliJ IDEA and it doesn't allow me to change anything in the Dart default setup.
UPD: Tried to use
import 'dart:html' show querySelector, Element
to import only that method and class, but file size is still 182kb.
The only solution I see for now is to make a few stripped versions of the default 'dart:html' package. The one without WebGL, SVG and some other features.
Because maybe Dart compiler works good, but there is just some methods and classes that I don't use, but the code uses. Like.. the initial package methods checking if some elements are SVG or something like that.
There is a tool for analyzing the output of a dart2js build, especially for references and dependencies. Just tested and gave a better overview in my case.
https://github.com/dart-lang/dump-info-visualizer
hosted :
https://dart-lang.github.io/dump-info-visualizer/
Build with option --dump-info
https://webdev.dartlang.org/tools/dart2js#options
Even when you don't import anything you will get some minimal output size. Dart provides a lot of features like classes with inheritance and mixins (and a lot more) and dart2js output contains code that implements these features.
This is like adding a JS library like jQuery.
Therefore main() {} will already result in an output size of several dozen kb. Adding another line of code probably will only add a few additional bytes.
pub build by default does tree-shaking and minifications, therefore no additional options are required.
Related
I have to make some functions that will use different lanaguages (python, R, js).
I got stuck at the part of generating random numbers in Python to initialize a list with random elements. I looked up on ways of initializing random lists, and then I decided to use result = polyglot.eval("python", "[random.randint(0,10) for i in range(20)];").
The problem that I face now is that I need to import the "random" library from python, or whatever libraries will I need from different languages. I heard that it might be a problem with the dependencies, but I am not sure...
What am I supposed to do? Is it even possible to import libraries from more languages in a single project? What other alternatives do I have?
Note that solution for different dynamic languages may differ.
Also js component is stable, while python (as of 2021) is still experimental.
Here is example for Python with modules
https://github.com/paulvi/java-python-graalvm-template
And if you really do polyglot (using Python object in Java code),
see https://github.com/hpi-swa-lab/graalpython-java-example
There is still issue how to actually deploy this in production
https://github.com/hpi-swa-lab/graalpython-java-example/issues/6
as just bundling venv subfolder into jar, will just work.
One solution is in ttps://github.com/paulvi/java-python-graalvm-template
Also randon, i.e. any library with graalvm is still big issue, as different packages have different issues, see https://github.com/oracle/graalpython/issues/228
I suggest, that before really mixing a lot of languages, just try one, e.g. js that is more stable, make it work, and then try next.
BTW PyCharm does not yet support graalpython.
If you do any open source, or later find somethin new, please let me know via GitHub issue
I'm already using uncss with grunt, but stumbled upon purifycss.
I can't seem to find comparisons anywhere.
Can anyone tell me the difference between the two to help me choose the right one?
UnCSS removes unused CSS from your stylesheets.
PurifyCSS does not modify the original CSS files.
I use PurifyCSS and I full recommend.
I hope that simplify the things for you, everyone has a way to do the things. If I were you I would test both and see which one is more helpful for you.
EDIT:
PurifyCSS takes also care about JS-Files which could add CSS classes and IDs.
Here is a more recent comparison, courtesy of another similar project, purgecss: https://www.purgecss.com/comparison.html
Summary
PurifyCSS
Works with any file type, not just HTML or JS
Uses extractors, which takes the content of a file and extracts the list of CSS selectors used in it
UnCSS
Effective at removing unused selectors from web apps due to HTML emulation and JS execution.
This has a performance cost.
Most accurate tool if you don't use server-side rendering.
No extractor for JS files, but developers can create extractors for specific frameworks and file types.
I'm trying to use YGuard to obfuscate some parts of my program which contain encryption methods and other sensitive information (which I'll further protect in other ways once I figure this out).
Because the program is quite complex and contains quite many libraries it obviously gives a series of warning and finally fails with:
WARNING: Method initialize_ffi_type is native but com/sun/jna/Native is not kept/exposed.
WARNING: Method getAPIChecksum is native but com/sun/jna/Native is not kept/exposed.
[...]
yGuard was unable to resolve a class (java.lang.ClassNotFoundException: com.sun.tools.javac.parser.Parser$Factory)
Now whatever that means I'd like to
exclude libraries which being all open source have nothing to hide so far
obfuscate just the methods and variables of some Class or some package and leave the rest untouched.
So far in YGuard it seems I have to specify what I don't want to be obfuscated, however I have far too many classes, I'd like instead to do the opposite: Specify what I'd like to obfuscate and proceed increasing the number of Classes and packages I want obfuscated.
Thanks
It is the normal practice for obfuscators to specify what should be kept and not the other way around.
However, you can define library classpaths with the externalclasses rule (link). Classes that are defined in this path are neither obfuscated nor shrinked. The second error you are getting (ClassNotFoundException) indicates that you have not specified all libraries that your project depends on.
In order to obfuscate your code now, what you could do is:
Pack the code that you want to be obfuscated in one jar and define everything else as a library
use a patternset in your keep rule (link) to define everything to be kept except the classes that you want to have obfuscated.
I’ve spent some time researching this and though I’ve found some relevant info,
Here’s what I’ve found:
SO question: “What is the clojure equivalent of the Python idiom if __name__ == '__main__'?”
Some techniques at RosettaCode
A few discussions in the Cojure Google Group — most from 2009
but none of them have answered the question satisfactorily.
My Clojure source code file defines a namespace and a bunch of functions. There’s also a function which I want to be invoked when the source file is run as a script, but never when it’s imported as a library.
So: now that it’s 2012, is there a way to do this yet, without AOT compilation? If so, please enlighten me!
I'm assuming by run as a script you mean via clojure.main as follows:
java -cp clojure.jar clojure.main /path/to/myscript.clj
If so then there is a simple technique: put all the library functions in a separate namespace like mylibrary.clj. Then myscript.clj can use/require this library, as can your other code. But the specific functions in myscript.clj will only get called when it is run as a script.
As a bonus, this also gives you a good project structure, as you don't want script-specific code mixed in with your general library functions.
EDIT:
I don't think there is a robust within Clojure itself way to determine whether a single file was launched as a script or loaded as a library - from Clojure's perspective, there is no difference between the two (it all gets loaded in the same way via Compiler.load(...) in the Clojure source for anyone interested).
Options if you really want to detect the manner of the launch:
Write a main class in Java which sets a static flag then launched the Clojure script. You can easily test this flag from Clojure.
Use AOT compilation to implement a Clojure main class which sets a flag
Use *command-line-args* to indicate script usage. You'll need to pass an extra parameter like "script" on the command line.
Use a platform-specific method to determine the command line (e.g. from the environment variables in Windows)
Use the --eval option in the clojure.main command line to load your clj file and launch a specific function that represents your script. This function can then set a script-specific flag if needed
Use one of the methods for detecting the Java main class at runtime
I’ve come up with an approach which, while deeply flawed, seems to work.
I identify which namespaces are known when my program is running as a script. Then I can compare that number to the number of namespaces known at runtime. The idea is that if the file is being used as a lib, there should be at least one more namespace present than in the script case.
Of course, this is extremely hacky and brittle, but it does seem to work:
(defn running-as-script
"This is hacky and brittle but it seems to work. I’d love a better
way to do this; see http://stackoverflow.com/q/9027265"
[]
(let
[known-namespaces
#{"clojure.set"
"user"
"clojure.main"
"clj-time.format"
"clojure.core"
"rollup"
"clj-time.core"
"clojure.java.io"
"clojure.string"
"clojure.core.protocols"}]
(= (count (all-ns)) (count known-namespaces))))
This might be helpful: the github project lein-oneoff describes itself as "dependency management for one-off, single-file clojure programs."
This lets you define everything in one file, but you do need the oneoff plugin installed in order to run it from the command line.
I have files named xxx.java.i,xxx.java.d,xxx.jar.i. I know that these file are somehow related to Java. What does this extension mean and for what is it used? Is it same type as the .class extension?
You should look at your build system for more information. It is possible that these are intermediate files that get transformed and renamed to ".java". For example, I've seen various build systems that use the ".i" suffix to mean "input", and perform various forms of variable substitution (e.g. changing something like "{VERSION_NUMBER}" to the version number of the library being compiled).
I think they are created by someone to serve his own purpose and unless we ask the author or see the content we won't know what it the purpose is.
If you see garbled characters, it's probably java bytecode and you can use some decompiler to see the code (see: How do I "decompile" Java class files?).