{
 "cells": [
  {
   "cell_type": "markdown",
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   "source": [
    "# Netrc: Managing your login credentials\n",
    "\n",
    "`.netrc` is a file that contains login information for various servers. It’s used by programs that need to log in to servers. You can add login information to a `.netrc` file in your home to avoid supplying username and password each time you download data. \n",
    "\n",
    "**DataDownloader** provides a `Netrc` class to manage your `.netrc` file. The details of the class can be found [here](https://data-downloader.readthedocs.io/en/latest/api/netrc.html).\n",
    "\n",
    "Following codes show how to using the `Netrc` class to manage your `.netrc` file.\n",
    "\n",
    "## Import and create a Netrc object"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "{}"
      ]
     },
     "execution_count": 3,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "from data_downloader import downloader\n",
    "\n",
    "netrc = downloader.Netrc()\n",
    "netrc.hosts"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Add a new credential record"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "{'urs.earthdata.nasa.gov': ('username', '', 'passwd')}"
      ]
     },
     "execution_count": 4,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "netrc.add(\"urs.earthdata.nasa.gov\", \"username\", \"passwd\")\n",
    "netrc.hosts"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "The new record is added to the `.netrc` file in the user's home directory. For Linux and MacOS, the file is located at `~/.netrc`. For Windows, the file is located at `%HOME%\\.netrc`."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "machine urs.earthdata.nasa.gov\n",
      "\tlogin username\n",
      "\tpassword passwd\n"
     ]
    }
   ],
   "source": [
    "!cat ~/.netrc"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "If the record already exists, you need set `overwrite=True` to overwrite it."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "machine urs.earthdata.nasa.gov\n",
       "\tlogin username\n",
       "\tpassword passwd_new"
      ]
     },
     "execution_count": 7,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "netrc.add(\"urs.earthdata.nasa.gov\", \"username\", \"passwd_new\", overwrite=True)\n",
    "netrc"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Get the host from the url\n",
    "\n",
    "If you don't know the host of the server, you can use the `get_url_host` function to get it by the url."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "'gpm1.gesdisc.eosdis.nasa.gov'"
      ]
     },
     "execution_count": 4,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "url = \"https://gpm1.gesdisc.eosdis.nasa.gov/daac-bin/OTF/HTTP_services.cgi?FILENAME=%2Fdata%2FGPM_L3%2FGPM_3IMERGM.06%2F2000%2F3B-MO.MS.MRG.3IMERG.20000601-S000000-E235959.06.V06B.HDF5&FORMAT=bmM0Lw&BBOX=31.904%2C99.492%2C35.771%2C105.908&LABEL=3B-MO.MS.MRG.3IMERG.20000601-S000000-E235959.06.V06B.HDF5.SUB.nc4&SHORTNAME=GPM_3IMERGM&SERVICE=L34RS_GPM&VERSION=1.02&DATASET_VERSION=06&VARIABLES=precipitation\"\n",
    "\n",
    "downloader.get_url_host(url)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "machine urs.earthdata.nasa.gov\n",
       "\tlogin username\n",
       "\tpassword passwd\n",
       "machine gpm1.gesdisc.eosdis.nasa.gov\n",
       "\tlogin username\n",
       "\tpassword passwd"
      ]
     },
     "execution_count": 5,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "netrc.add(downloader.get_url_host(url), \"username\", \"passwd\")\n",
    "netrc"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Remove credential records\n",
    "\n",
    "If you want to remove a record from the `.netrc` file, you can use the `remove` method."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "machine urs.earthdata.nasa.gov\n",
       "\tlogin username\n",
       "\tpassword passwd"
      ]
     },
     "execution_count": 7,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "netrc.remove(downloader.get_url_host(url))\n",
    "netrc"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "If you want to remove all records from the `.netrc` file, you can use the `clear` method."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": []
     },
     "execution_count": 8,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "netrc.clear()\n",
    "netrc"
   ]
  }
 ],
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