refactor(weather): Fix timeout, reduce calls, apply shellcheck

scripts/weather.sh

@@ -1,97 +1,129 @@
 #!/usr/bin/env bash
 # setting the locale, some users have issues with different locales, this forces the correct one
-export LC_ALL=C.utf8
+export LC_ALL=en_US.UTF-8
 
-fahrenheit=$1
-location=$2
-fixedlocation=$3
+API_URL="https://wttr.in"
+DELIM=":"
 
 # emulate timeout command from bash - timeout is not available by default on OSX
 if [ "$(uname)" == "Darwin" ]; then
-  timeout() {
-      perl -e 'alarm shift; exec @ARGV' "$duration" "$@"
+  function timeout() {
+    local _duration
+    _duration="${1:-1}"
+    command -p perl -e 'alarm shift; exec @ARGV' "$_duration" "$@"
   }
 fi
 
-display_location()
-{
-  if $location && [[ ! -z "$fixedlocation" ]]; then
-    echo " $fixedlocation"
-  elif $location; then
-    city=$(curl -s https://ipinfo.io/city 2> /dev/null)
-    region=$(curl -s https://ipinfo.io/region 2> /dev/null)
-    echo " $city, $region"
-  else
-    echo ''
-  fi
-}
+# Fetch weather information from remote API
+# Globals:
+#   API_URL
+#   DELIM
+# Arguments:
+#   show fahrenheit, either "true" or "false"
+#   optional fixed location to query weather data about
+function fetch_weather_information() {
+  local _show_fahrenheit _location _unit
+  _show_fahrenheit="$1"
+  _location="$2"
 
-fetch_weather_information()
-{
-  display_weather=$1
-  # it gets the weather condition textual name (%C), and the temperature (%t)
-  api_response=$(curl -sL wttr.in/${fixedlocation// /%20}\?format="%C+%t$display_weather")
-
-  if [[ $api_response = "Unknown location;"* ]]; then
-    echo "Unknown location error"
+  if "$_show_fahrenheit"; then
+    _unit="u"
   else
-    echo $api_response
+    _unit="m"
   fi
+
+  # If the user provies a "fixed location", `@dracula-fixed-location`, that the
+  # API does not recognize, the API may suggest a users actual geoip GPS
+  # location in the response body. This can lead to user PI leak.
+  # Drop response body when status code >= 400 and return nonzero by passing the
+  # `--fail` flag. Execute curl last to allow the consumer to leverage the
+  # return code. Pass `--show-error` and redirect stderr for the consumer.
+  command -p curl -L --silent --fail --show-error \
+    "${API_URL}/${_location// /%20}?format=%C${DELIM}%t${DELIM}%l&${_unit}" 2>&1
 }
 
-#get weather display
-display_weather()
-{
-  if $fahrenheit; then
-    display_weather='&u' # for USA system
-  else
-    display_weather='&m' # for metric system
-  fi
-  weather_information=$(fetch_weather_information $display_weather)
+# Format raw weather information from API
+# Globals:
+#   DELIM
+# Arguments:
+#   The raw weather data as returned by "fetch_weather_information()"
+#   show location, either "true" or "false"
+function format_weather_info() {
+  local _raw _show_location
+  _raw="$1" # e.g. "Rain:+63°F:Houston, Texas, United States"
+  _show_location="$2"
 
-  weather_condition=$(echo "$weather_information" | awk -F' -?[0-9]' '{print $1}' | xargs) # Extract condition before temperature, e.g. Sunny, Snow, etc
-  temperature=$(echo "$weather_information" | grep -oE '[-+]?[0-9]+°[CF]') # Extract temperature, e.g. +31°C, -3°F, etc
-  unicode=$(forecast_unicode $weather_condition)
+  local _weather _temp _location
+  _weather="${_raw%%"${DELIM}"*}"                                  # slice temp and location to get weather
+  _weather=$(printf '%s' "$_weather" | tr '[:upper:]' '[:lower:]') # lowercase weather, OSX’s bash3.2 does not support ${v,,}
+  _temp="${_raw#*"${DELIM}"}"                                      # slice weather to get temp and location
+  _temp="${_temp%%"${DELIM}"*}"                                    # slice location to get temp
+  _temp="${_temp/+/}"                                              # slice "+" from "+74°F"
+  _location="${_raw##*"${DELIM}"}"                                 # slice weather and temp to get location
+  [ "${_location//[^,]/}" == ",," ] && _location="${_location%,*}" # slice country if it exists
 
-  # Mac Only variant should be transparent on Linux
-  if [[ "${temperature/+/}" == *"===="* ]]; then
-    temperature="error"
-  fi
+  case "$_weather" in
+  'snow')
+    _weather='❄'
+    ;;
+  'rain' | 'shower')
+    _weather='☂'
+    ;;
+  'overcast' | 'cloud')
+    _weather='☁'
+    ;;
+  'na')
+    _weather=''
+    ;;
+  *)
+    _weather='☀'
+    ;;
+  esac
 
-  if [[ "${temperature/+/}" == "error" ]]; then
-    # Propagate Error
-    echo "error"
+  if "$_show_location"; then
+    printf '%s %s %s' "$_weather" "$_temp" "$_location"
   else
-    echo "$unicode ${temperature/+/}" # remove the plus sign to the temperature
+    printf '%s %s' "$_weather" "$_temp"
   fi
 }
 
-forecast_unicode()
-{
-  weather_condition=$(echo $weather_condition | awk '{print tolower($0)}')
-
-  if [[ $weather_condition =~ 'snow' ]]; then
-    echo '❄ '
-  elif [[ (($weather_condition =~ 'rain') || ($weather_condition =~ 'shower')) ]]; then
-    echo '☂ '
-  elif [[ (($weather_condition =~ 'overcast') || ($weather_condition =~ 'cloud')) ]]; then
-    echo '☁ '
-  elif [[ $weather_condition = 'NA' ]]; then
-    echo ''
-  else
-    echo '☀ '
-  fi
-}
+# Display weather, temperature, and location
+# Globals
+#   none
+# Arguments
+#   show fahrenheit, either "true" (default) or "false"
+#   show location, either "true" (default) or "false"
+#   optional fixed location to query data about, e.g. "Houston, Texas"
+function main() {
+  local _show_fahrenheit _show_location _location
+  _show_fahrenheit="${1:-true}"
+  _show_location="${2:-true}"
+  _location="$3"
 
-main()
-{
   # process should be cancelled when session is killed
-  if timeout 1 bash -c "</dev/tcp/ipinfo.io/443" && timeout 1 bash -c "</dev/tcp/wttr.in/443" && [[ "$(display_weather)" != "error" ]]; then
-    echo "$(display_weather)$(display_location)"
-  else
-    echo "Weather Unavailable"
+  if ! timeout 1 bash -c "</dev/tcp/wttr.in/443"; then
+    printf 'Weather Unavailable\n'
+    return
+  fi
+
+  # BashFAQ/002: assignment of substitution does not effect status code.
+  local _resp
+  if ! _resp=$(fetch_weather_information "$_show_fahrenheit" "$_location"); then
+
+    # e.g. "curl: (22) The requested URL returned error: 404"
+    case "${_resp##* }" in
+    404)
+      printf 'Unknown Location\n'
+      ;;
+    *)
+      printf 'Weather Unavailable\n'
+      ;;
+    esac
+
+    return
   fi
+
+  format_weather_info "$_resp" "$_show_location"
 }
 
-#run main driver program
-main
+main "$@"

scripts/weather_wrapper.sh

@@ -2,30 +2,35 @@
 # setting the locale, some users have issues with different locales, this forces the correct one
 export LC_ALL=en_US.UTF-8
 
-#wrapper script for running weather on interval
-
-fahrenheit=$1
-location=$2
-fixedlocation=$3
-
-DATAFILE=/tmp/.dracula-tmux-data
+DATAFILE="/tmp/.dracula-tmux-data"
 LAST_EXEC_FILE="/tmp/.dracula-tmux-weather-last-exec"
-RUN_EACH=1200
-TIME_NOW=$(date +%s)
-TIME_LAST=$(cat "${LAST_EXEC_FILE}" 2>/dev/null || echo "0")
+INTERVAL=1200
 
-main()
-{
-  current_dir="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+# Call weather script on interval to prevent exhausting remote API
+# Globals:
+#   DATAFILE
+#   LAST_EXEC_FILE
+#   INTERVAL
+# Arguments:
+#   show fahrenheit, either "true" (default) or "false"
+#   show location, either "true" (default) or "false"
+#   optional fixed location to query data about, e.g. "Houston, Texas"
+function main() {
+  local _show_fahrenheit _show_location _location _current_dir _last _now
+  _show_fahrenheit="$1"
+  _show_location="$2"
+  _location="$3"
+  _current_dir="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+  _last=$(cat "$LAST_EXEC_FILE" 2>/dev/null || echo 0)
+  _now=$(date +%s)
 
-  if [ "$(expr ${TIME_LAST} + ${RUN_EACH})" -lt "${TIME_NOW}" ]; then
+  if (((_now - _last) > INTERVAL)); then
     # Run weather script here
-    $current_dir/weather.sh $fahrenheit $location "$fixedlocation" > "${DATAFILE}"
-    echo "${TIME_NOW}" > "${LAST_EXEC_FILE}"
+    "${_current_dir}/weather.sh" "$_show_fahrenheit" "$_show_location" "$_location" >"${DATAFILE}"
+    printf '%s' "$_now" >"${LAST_EXEC_FILE}"
   fi
 
   cat "${DATAFILE}"
 }
 
-#run main driver function
-main
+main "$@"