Reply from REST can come in pieces

It is not given that one reply comes in one piece. It might come n
multiple messages and we need to connect them before trying to parse
them.

Fixes cockpit-project#1025

src/rest.js

@@ -20,12 +20,21 @@ function connect(address, system) {
 
     connection.monitor = function(options, callback, system, return_raw) {
         return new Promise((resolve, reject) => {
+            let buffer = "";
+
             http.request(options)
                     .stream(data => {
                         if (return_raw)
                             callback(data);
-                        else
-                            callback(JSON.parse(data));
+                        else {
+                            buffer += data;
+
+                            const chunks = buffer.split("\0");
+                            buffer = chunks.pop();
+
+                            for (let i = 0; i < chunks.length; i += 1)
+                                callback(JSON.parse(chunks[i]));
+                        }
                     })
                     .catch((error, content) => {
                         manage_error(reject, error, content);

test/check-application

@@ -2122,6 +2122,15 @@ class TestApplication(testlib.MachineCase):
         self.execute(auth, f"podman inspect --format '{{{{.Id}}}}' {container_name_new}").strip()
         self.waitContainerRow(container_name_new)
 
+    def testMultipleContainers(self):
+        # Create 31 containers
+        for i in range(31):
+            self.execute(True, f"podman run -dt --name container{i} quay.io/libpod/busybox:latest")
+
+        self.login()
+
+        self.waitContainerRow("container30")
+
 
 if __name__ == '__main__':
     testlib.test_main()