Some improvements to install.sh (#2738)

* Added --show-error flag to curl command line

This change will show more information when the download fails.

  -S, --show-error
      When used with -s, --silent, it makes curl show an error message if it fails.

* Reuse download functions

* Remove tmp files after use

install.sh

@@ -102,11 +102,12 @@ getFile() {
   GETFILE_URL="$1"
   GETFILE_FILE_PATH="$2"
   if [ "$DOWNLOAD_TOOL" = "curl" ]; then
-    GETFILE_HTTP_STATUS_CODE=$(curl -s -w '%{http_code}' -L "$GETFILE_URL" -o "$GETFILE_FILE_PATH")
+    GETFILE_HTTP_STATUS_CODE=$(curl --silent --show-error --write-out '%{http_code}' --location "$GETFILE_URL" -o "$GETFILE_FILE_PATH")
   elif [ "$DOWNLOAD_TOOL" = "wget" ]; then
     TMP_FILE=$(mktemp)
     wget --server-response --content-on-error -q -O "$GETFILE_FILE_PATH" "$GETFILE_URL" 2>"$TMP_FILE"
     GETFILE_HTTP_STATUS_CODE=$(awk '/^  HTTP/{print $2}' "$TMP_FILE")
+    rm -f "$TMP_FILE"
   fi
   echo "$GETFILE_HTTP_STATUS_CODE"
 }
@@ -155,15 +156,10 @@ downloadFile() {
       echo "Trying to find a release using the GitHub API."
 
       LATEST_RELEASE_URL="https://api.github.com/repos/${PROJECT_OWNER}/$PROJECT_NAME/releases/tags/$TAG"
-      if [ "$DOWNLOAD_TOOL" = "curl" ]; then
-        HTTP_RESPONSE=$(curl -sL --write-out 'HTTPSTATUS:%{http_code}' "$LATEST_RELEASE_URL")
-        HTTP_STATUS_CODE=$(echo "$HTTP_RESPONSE" | tr -d '\n' | sed -e 's/.*HTTPSTATUS://')
-        BODY=$(echo "$HTTP_RESPONSE" | sed -e 's/HTTPSTATUS\:.*//g')
-      elif [ "$DOWNLOAD_TOOL" = "wget" ]; then
-        TMP_FILE=$(mktemp)
-        BODY=$(wget --server-response --content-on-error -q -O - "$LATEST_RELEASE_URL" 2>"$TMP_FILE" || true)
-        HTTP_STATUS_CODE=$(awk '/^  HTTP/{print $2}' "$TMP_FILE")
-      fi
+      TMP_BODY_FILE=$(mktemp)
+      HTTP_STATUS_CODE=$(getFile "$LATEST_RELEASE_URL" "$TMP_BODY_FILE")
+      BODY=$(cat "$TMP_BODY_FILE")
+      rm -f "$TMP_BODY_FILE"
       if [ "$HTTP_STATUS_CODE" != 200 ]; then
         echo "Request failed with HTTP status code $HTTP_STATUS_CODE"
         fail "Body: $BODY"