62 lines
2.3 KiB
Plaintext
62 lines
2.3 KiB
Plaintext
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= SandboxOS App Development Guide =
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This is a brief introduction on developing SandboxOS apps targeted at people who are already familiar with web development.
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== Packages ==
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A package is a directory of files. '''package.json''' is the only file with special meaning.
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Here is an example package.json:
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{{{
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#!json
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{
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"name": "chat",
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"start": "backend.js",
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"imports": ["auth", "httpd", "filesystem"],
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"href": "/chat",
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"description": "A basic multi-user chat example."
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}
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}}}
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* '''name''': identifies the package. If it is not unique, any existing installed package of the same name will be replaced when installing the package.
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* '''start''': specifies the JavaScript file which is the entry point of the task. When a new process is started for this package, this script is executed within it.
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* '''imports''': list of package/task names which this package wants to be able to access.
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* '''href''': link to the task's entry page used by [/tasks /tasks].
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* '''description''': human-readable description of the package, displayed by [/tasks /tasks].
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== Promises ==
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JavaScript promises are used heavily. Invoking any method on another task will return a Promise object. Execution will return immediately but go asynchronous. That usually looks like this:
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{{{
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#!javascript
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imports.email.sendMessage(message).then(function(result) {
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// When sendMessage completes, result is the return value.
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}).catch(function(error) {
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// If sendMessage fails (or calling it somehow fails), error is the reason.
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});
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// sendMessage returns immediately and execution continues on.
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}}}
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This is a completely inadequate explanation of the nuances involved, but it's a starting point. Promises can be created and chained and combined in interesting ways.
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== Inter-Task Communication ==
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Tasks have access to the exported functions on any task declared in their package imports.
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In addition, functions passed between tasks can be called by the receiving task or passed along further.
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Here is an untested, made-up example with two hypothetical tasks, '''math''' and '''test''':
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'''math.js''':
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{{{
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#!javascript
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exports = {
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sum: function(a, b) { return a + b; },
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multiply: function(a, b) { return a * b; },
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};
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}}}
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'''test.js''':
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{{{
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#!javascript
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imports.math.sum(4, 5).then(function(result) {
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// result === 9
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});
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}}}
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