fix(skytrace): improve handling of JSON responses (#1957)

- Parse JSON responses and pass them as objects to expectation
  functions
- Ignore JSON parsing errors unless we actually need to use the
  response (e.g. to pretty-print or for a JSON-specific expectation)

packages/skytrace/src/commands/ping.ts

@@ -433,31 +433,44 @@ class PingCommand extends Command {
       const isJSON = contentType.match(/json/gi);
       const isXML = contentType.match(/html/gi) || contentType.match(/xml/gi);
 
-      if (flags.showBody) {
-        let language;
-        if (isJSON) {
-          language = 'json';
-        }
-        if (isXML) {
-          language = 'html';
+      let body = context.vars.body;
+      let isBodyValidJSON = false;
+      if (isJSON) {
+        // Try to parse the body as JSON. Errors are ignored because as a
+        // general purpose HTTP client we don't want to fail on invalid
+        // JSON by default - only if the user explicitly or implicitly
+        // specifies that the body needs to be valid.
+        try {
+          body = JSON.parse(context.vars.body);
+          isBodyValidJSON = true;
+        } catch (_parseErr) {
         }
+      }
 
-        if (language) {
-          let output = context.vars.body;
-          if (language === 'json' && flags.pretty) {
-            output = JSON.stringify(JSON.parse(context.vars.body), null, 4);
-          }
-          this.log(highlight(output, { language }));
-        } else {
+      // If -b is set without -p -- just print the body as-is.
+      // If -bp is set - pretty-print JSON or XML/HTML, otherwise print the body as-is.
+      if (flags.showBody) {
+        if (!flags.pretty) {
           this.log(context.vars.body);
+        } else {
+          if (isJSON) {
+            if (!isBodyValidJSON) {
+              this.log(chalk.red('Could not parse body is valid JSON for pretty-printing'));
+            } else {
+              this.log(highlight(JSON.stringify(body, null, 4), { language: 'json' }));
+            }
+          } else if (isXML) {
+            this.log(highlight(context.vars.body, { language: 'html' }));
+          } else {
+            this.log(context.vars.body);
+          }
         }
       }
 
       if (flags.jmespath || flags.cheerio || flags.q) {
         if (flags.jmespath || (isJSON && flags.q)) {
           try {
-            const json = JSON.parse(context.vars.body);
-            const result = jmespath.search(json, flags.jmespath || flags.query);
+            const result = jmespath.search(body, flags.jmespath || flags.query);
 
             // If our output is piped we want to print the JSON without highlighting:
             if (process.stdout.isTTY) {
@@ -473,7 +486,7 @@ class PingCommand extends Command {
           }
         } else if (flags.cheerio || (isXML && flags.query)) {
           try {
-            const $ = cheerio.load(context.vars.body);
+            const $ = cheerio.load(body);
             const elts = $(flags.cheerio || flags.query).html();
             // If our output is piped we want to print the without highlighting:
             if (process.stdout.isTTY) {
@@ -503,7 +516,7 @@ class PingCommand extends Command {
           let result = expectations[checker].call(
             this,
             ex,
-            context.vars.body,
+            body,
             context.vars.req,
             context.vars.res,
             {}