[start_ursim.sh] Use direct web pages instead of GitHub API to download URCap (#308)

The API is rate-restricted on an IP address level. And with IPv4 that IP
address is potentially shared between many users of the same ISP.

This PR uses the release web pages to find the latest release.
Basically, it uses the link to the latest release which will be
forwarded by GitHub to a web page using the latest version. Thus, we can
get the latest tag from the redirected URL and use that to build a valid
download link for the latest release.

Author: urfeex

scripts/start_ursim.sh

@@ -29,7 +29,7 @@
 # POSSIBILITY OF SUCH DAMAGE.
 
 PERSISTENT_BASE="${HOME}/.ursim"
-URCAP_VERSION="" # If not set, the latest version will be downloaded
+URCAP_VERSION="latest"
 IP_ADDRESS="192.168.56.101"
 PORT_FORWARDING_WITH_DASHBOARD="-p 30001-30004:30001-30004 -p 29999:29999"
 PORT_FORWARDING_WITHOUT_DASHBOARD="-p 30001-30004:30001-30004"
@@ -212,15 +212,58 @@ post_setup_e-series()
   post_setup_cb3
 }
 
+get_effective_url()
+{
+  curl -Ls -o /dev/null -w %\{url_effective\} "$1"
+}
+
+get_version_from_release_url()
+{
+  echo "$effective_url" | grep -oP '\d+\.\d+\.\d+' | head -n 1
+}
+
+# Get the latest tag from a GitHub release page. Provide a link to its latest release e.g.
+# https://github.com/UniversalRobots/Universal_Robots_ExternalControl_URCapX/releases/latest
+get_latest_release_tag()
+{
+  effective_url=$(get_effective_url "$1")
+  get_version_from_release_url "$effective_url"
+}
+
+# Get the URCAPX download URL for a given version
+#
+# Specify the desired version or "latest" as the first argument
+# 
+# sets URCAPX_VERSION
+# sets URCAPX_DOWNLOAD_URL
+get_download_url_urcapx()
+{
+  release_url="https://github.com/UniversalRobots/Universal_Robots_ExternalControl_URCapX/releases/$1"
+  URCAPX_VERSION=$(get_latest_release_tag "$release_url")
+  URCAPX_DOWNLOAD_URL="https://github.com/UniversalRobots/Universal_Robots_ExternalControl_URCapX/releases/download/$URCAPX_VERSION/external-control-$URCAPX_VERSION.urcapx"
+}
+
+# Get the URCAPX download URL for a given version
+#
+# Specify the desired version or "latest" as the first argument
+#
+# sets URCAPX_VERSION
+# sets URCAPX_DOWNLOAD_URL
+get_download_url_urcap()
+{
+  release_url="https://github.com/UniversalRobots/Universal_Robots_ExternalControl_URCap/releases/$1"
+  URCAP_VERSION=$(get_latest_release_tag "$release_url")
+  URCAP_DOWNLOAD_URL="https://github.com/UniversalRobots/Universal_Robots_ExternalControl_URCap/releases/download/v$URCAP_VERSION/externalcontrol-$URCAP_VERSION.jar"
+}
+
 post_setup_polyscopex()
 {
-  urcapx_download_url=$(curl -s https://api.github.com/repos/UniversalRobots/Universal_Robots_ExternalControl_URCapX/releases/latest | grep "browser_download_url.*urcapx" | cut -d ":" -f 2,3 | tr -d "\"[:space:]")
-  URCAPX_VERSION=$(echo "$urcapx_download_url" | grep -oP '\d+\.\d+\.\d+' | head -n 1)
+  get_download_url_urcapx latest
   mkdir -p "${URCAP_STORAGE}"
-  urcapx_file="${URCAP_STORAGE}/external_control-$URCAPX_VERSION.urcapx"
+  urcapx_file="${URCAP_STORAGE}/external-control-$URCAPX_VERSION.urcapx"
   if [[ ! -f "$urcapx_file" ]]; then
     echo "Downloading External Control URCapX version ${URCAPX_VERSION}"
-    curl -L -o "$urcapx_file" "$urcapx_download_url"
+    curl -L -o "$urcapx_file" "$URCAPX_DOWNLOAD_URL"
   fi
 
   echo -ne "Starting URSim. Waiting for UrService to be up..."
@@ -383,13 +426,10 @@ main() {
     PROGRAM_STORAGE=$(realpath "$PROGRAM_STORAGE")
 
     # Download external_control URCap
-    if [[ -z "$URCAP_VERSION" ]]; then
-      urcap_download_url=$(curl -s https://api.github.com/repos/UniversalRobots/Universal_Robots_ExternalControl_URCap/releases/latest | grep "browser_download_url.*jar" | cut -d ":" -f 2,3 | tr -d "\"[:space:]")
-      URCAP_VERSION=$(echo "$urcap_download_url" | grep -oP '\d+\.\d+\.\d+' | head -n 1)
-    fi
+    get_download_url_urcap $URCAP_VERSION
     if [[ ! -f "${URCAP_STORAGE}/externalcontrol-${URCAP_VERSION}.jar" ]]; then
       echo "Downloading and installing External Control URCap version ${URCAP_VERSION}"
-      curl -L -o "${URCAP_STORAGE}/externalcontrol-${URCAP_VERSION}.jar" "$urcap_download_url"
+      curl -L -o "${URCAP_STORAGE}/externalcontrol-${URCAP_VERSION}.jar" "$URCAP_DOWNLOAD_URL"
     fi
     docker_cmd="docker run --rm -d --net ursim_net --ip $IP_ADDRESS\
       -v ${URCAP_STORAGE}:/urcaps \

tests/test_start_ursim.bats

@@ -7,6 +7,28 @@ setup() {
     source $DIR/../scripts/start_ursim.sh
 }
 
+@test "test_get_version_from_release_url" {
+  effective_url="https://github.com/UniversalRobots/Universal_Robots_ExternalControl_URCapX/releases/0.1.0"
+
+  VERSION=$(get_version_from_release_url "$effective_url")
+
+  [ "$VERSION" = "0.1.0" ]
+}
+
+@test "test_get_download_url_urcapx" {
+  get_download_url_urcapx "0.1.0"
+  echo "Download URL: $URCAPX_DOWNLOAD_URL"
+  echo "URCAPX_VERSION: $URCAPX_VERSION"
+  [ "$URCAPX_DOWNLOAD_URL" = "https://github.com/UniversalRobots/Universal_Robots_ExternalControl_URCapX/releases/download/0.1.0/external-control-0.1.0.urcapx" ]
+}
+
+@test "test_get_download_url_urcap" {
+  get_download_url_urcap "1.0.5"
+  echo "Download URL: $URCAP_DOWNLOAD_URL"
+  echo "URCAP_VERSION: $URCAP_VERSION"
+  [ "$URCAP_DOWNLOAD_URL" = "https://github.com/UniversalRobots/Universal_Robots_ExternalControl_URCap/releases/download/v1.0.5/externalcontrol-1.0.5.jar" ]
+}
+
 @test "test get_series_from_model" {
   get_series_from_model "ur10e"
   echo "ROBOT_SERIES: $ROBOT_SERIES"