CLion assumes that all development, debugging, and testing is done on your computer and then the code is deployed to a production environment.
The reason to stick to this "local development - deployment" model lies in the way CLion provides its coding assistance which includes code completion, code inspections & validations, code navigation, and so on. All this functionality is based on the project files index which CLion builds when the project is loaded and updates on the fly as you edit your code.
To provide efficient coding assistance, CLion needs to re-index code fast, which requires fast access to project files. The latter can be ensured only for local files, that is, files that are stored on you hard disk and are accessible through the file system.
Interaction between CLion and servers
Interaction between CLion and servers is controlled through server access configurations. Anytime you are going to use a server, you need to define a server access configuration, no matter whether your server is on a remote host or on your computer.
Taking into account all the above, let's define the following basic concepts related to synchronization between CLion and servers.
An in-place server is a server whose document root is the parent of the project root, either immediate or not. In other words, the Web server is running on your computer, your project is under its document root (for example, in the /htdocs folder), and you do your development directly on the server.
A local file/folder is any file or folder under the project root.
A remote file/folder is any file or folder on the server.
Upload is copying data from the project TO the server, either local or remote.
Download is copying data FROM the server to the project.
After you have configured synchronization with a server, you can upload, download, and manage files on it directly from CLion. Moreover, you can suppress uploading or downloading specific files or entire folders. Finally, you can optimize you workflow by configuring content roots so specific folders are not involved in indexing, which significantly saves project indexing time.
Synchronization with servers, uploading, downloading, and managing files on them are provided via the Remote Hosts Access bundled plugin, which is by default enabled. If the plugin is disabled, activate it in the Plugins page of the Settings dialog. For details, see Plugins.