# Front-End Monitoring Access

    # SPA (Single Page Application)

    1. Add the activation code of TA.js to the head of the frame page (usually index.html).

      <script src="/ta"></script>
<script>
  var _taConfig = window._taConfig;
  if (_taConfig && _taConfig.enabled) {
    !function(e,n,r,t,a,o,c){e[a]=e[a]||function(){(e[a].q=e[a].q||[]).push(arguments)},e.onerror=function(n,r,t,o,c){e[a]("sendExecError",n,r,t,o,c)},n.addEventListener("error",function(n){e[a]("sendError",n)},!0),o=n.createElement(r),c=n.getElementsByTagName(r)[0],o.async=1,o.src=t,c.parentNode.insertBefore(o,c)}(window,document,"script",_taConfig.url,"$ta");
    $ta('start', { udata: { uid: 0 }, ak: _taConfig.ak, url: _taConfig.collectorUrl });
  }
</script>

    2. Add /ta in nginx.conf to return the configuration of TA.js. Environment variables will be injected by default in Erda.

          set $taEnabled ${TERMINUS_TA_ENABLE};
    set $taUrl ${TERMINUS_TA_URL};
    set $collectorUrl ${TERMINUS_TA_COLLECTOR_URL};
    set $terminusKey ${TERMINUS_KEY};
    location /ta {
        default_type application/javascript;
        return 200 'window._taConfig={enabled:$taEnabled,ak:"$terminusKey",url:"$taUrl",collectorUrl:"$collectorUrl"}';
    }

    3. To collect user ID to add user-dimensional statistics, set userId to TA.js cache at the location where the front-end user queries.

      if (typeof window.$ta !== 'undefined') window.$ta('setUser', [userId])

    # Spring MVC

    1. Add the Config class to read TA.js environment variables, which will be injected by default in Erda.

      @Component
@Data
public class TaConfig {
    @Value("${terminus.ta.collector.url}")
    private String terminusTaCollectorURL;

    @Value("${terminus.ta.enable}")
    private boolean terminusTaEnable;

    @Value("${terminus.ta.url}")
    private String terminusTaURL;

    @Value("${terminus.key}")
    private String terminusKey;
}

    2. Add Controller to return TA.js configuration.

      @Slf4j
@RestController
@RequestMapping("/api/ta")
public class TaController {

    @Autowired
    private TaConfig config;

    @RequestMapping(produces = "application/javascript")
    @ResponseBody
    public String ta() {
        return String.format("window._taConfig={enabled:%b,ak:\"%s\",url:\"%s\",collectorUrl:\"%s\"}", config.isTerminusTaEnable(), config.getTerminusKey(), config.getTerminusTaURL(), config.getTerminusTaCollectorURL());
    }
}

    3. Add the TA.js activation code in the head of the page to be monitored.

      <head>
    <script src="/api/ta"></script>
    <script>
        var _taConfig = window._taConfig;
        if (_taConfig && _taConfig.enabled) {
            !function (e, n, r, t, a, o, c) {
                e[a] = e[a] || function () {
                    (e[a].q = e[a].q || []).push(arguments)
                }, e.onerror = function (n, r, t, o, c) {
                    e[a]("sendExecError", n, r, t, o, c)
                }, n.addEventListener("error", function (n) {
                    e[a]("sendError", n)
                }, !0), o = n.createElement(r), c = n.getElementsByTagName(r)[0], o.async = 1, o.src = t, c.parentNode.insertBefore(o, c)
            }(window, document, "script", _taConfig.url, "$ta");
            $ta('start', {udata: {uid: 0}, ak: _taConfig.ak, url: _taConfig.collectorUrl});
        }
    </script>
</head>

    # Herd

    1. Add terminus-key.js.

      module.exports = () => async (ctx, next) => {
  ctx.herdContext['_TERMINUS_KEY_'] = process.env.TERMINUS_KEY;
  ctx.herdContext['_TA_ENABLE_'] = process.env.TERMINUS_TA_ENABLE || false;
  ctx.herdContext['_TA_URL_'] = process.env.TERMINUS_TA_URL || '//static.terminus.io/ta.js';
  ctx.herdContext['_TA_COLLECT_URL_'] = process.env.TERMINUS_TA_COLLECTOR_URL || '//analytics.terminus.io/collect';
  await next();
}

    2. Add TA.js Script to the head of layout.hbs.

       <head>
    <script>
        {{#if _TA_ENABLE_}}
          !function(e,t,n,s,a,c,i){e[a]=e[a]||function(){(e[a].q=e[a].q||[]).push(arguments)},c=t.createElement(n),i=t.getElementsByTagName(n)[0],c.async=1,c.src=s,i.parentNode.insertBefore(c,i)}(window,document,"script","{{_TA_URL_}}","$ta");
          $ta('start',{ udata: { uid: {{#if _USER_}}{{_USER_.id}}{{else}}0{{/if}} }{{#if _TERMINUS_KEY_}}, ak: '{{_TERMINUS_KEY_}}'{{/if}} , url: '{{_TA_COLLECT_URL_}}' })
        {{/if}}
    </script>
  </head>

    3. To collect user ID to add user-dimensional statistics, set userId to TA.js cache at the location where the front-end user queries.

      if (typeof window.$ta !== 'undefined') window.$ta('setUser', [userId])

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