Abu Ashraf Masnun

Python

Fixing lxml installation on OS X

Post author By masnun
Post date July 14, 2015

I have recently upgraded to OS X Yosemite. And somehow my lxml installation broke. When I tried to do pip install lxml, I was getting an error: ‘libxml/xmlversion.h’ file not found. The error message is obvious. While trying to compile lxml, it can’t find the libxml header files. What was not very obvious to me is how to fix this. I am using Homebrew. I upgraded both libxml2 and libxslt. Didn’t work. After quite some googling and checking out some stack overflow answers, I found out my mistake. By default, brew wouldn’t link the libxml and libxslt to avoid conflicts. So I have to force them. In short, this is what I needed to do:

brew link libxml2 --force
brew link libxslt --force

1 2	brew link libxml2 --force brew link libxslt --force

Of course, if you didn’t have them installed before, you need to install them first:

brew install libxml2
brew install libxslt

1 2	brew install libxml2 brew install libxslt

If it doesn’t work even after force linking, you may want to first unlink previous versions.

brew unlink libxml2
brew unlink libxslt

1 2	brew unlink libxml2 brew unlink libxslt

Then I tried to install lxml from pip and it worked like a charm! 🙂

Javascript

ES6 on Node.js (And Heroku)

Post author By masnun
Post date July 11, 2015
5 Comments on ES6 on Node.js (And Heroku)

I will get straight to the point. ES6 is awesome and we want to use it in our Node.js project. We would use Babel to convert ES6 codes to ES5 compatible Javascript for Node. We first install Babel.

npm i babel -S

1	npm i babel -S

Now we write our awesome app in ES6:

// Filename: main.es6

import express from "express"


var app = express();

app.get("/", (req, res) => {
    res.json({hello: 'world'});
});


var port = process.env.PORT || 3000;

var server = app.listen(port, () => {
    console.log('Service started on port :' + port);
});

// Filename: main.es6

import express from "express"

var app = express();

app.get("/", (req, res) => {

res.json({hello: 'world'});

});

var port = process.env.PORT || 3000;

var server = app.listen(port, () => {

console.log('Service started on port :' + port);

});

We could use Babel to transpile ES6 to ES5 and then run the ES5 code in Node. But instead we shall directly run ES6 with the “babel-node” binary. The babel-node binary transpiles ES6 code in runtime. So we don’t need any watchers or manual transpilation.

We modify our package.json’s script’s section to add the babel-node binary:

"scripts": {
    "start": "./node_modules/.bin/babel-node  main.es6"
}

"scripts": {

"start": "./node_modules/.bin/babel-node main.es6"

}

Now if we push to Heroku, it will work fine 🙂

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