{:obj; ... :}
=============
**This feature is experimental.**
Executes a external script (currently only Python) and processes its output. The script receives parameters and can access the template schema.
JSON obj file
```html
{:obj; fileobj.json :}
```
JSON obj inline:
```html
{:obj;
{
"engine": "Python",
"file": "script.py",
"params": {},
"callback": "main",
"template": "template.ntpl"
}
:}
```
JSON obj template inline:
```html
{:obj;
{
"engine": "Python",
"file": "script.py",
"params": {},
"callback": "main"
}
>>
{:;local::varname:}
:}
```
The idea is to use a script that has its own template to assign values to the variables of that template. In a JSON file, an object with its properties, script to execute, template, etc., is defined.
Example Object:
```json
{
"engine": "Python", // Optional, default "Python"
"file": "script.py", // Required, path to script
"schema": false // Optional, default false
"venv": "/path/to/.env" // Optional, default none
"params": {}, // Optional, parameters passed to the script
"callback": "main", // Optional, default "main"
"template": "template.ntpl" // Optional, template to process the result
}
```
The keys "file", "params" and "template" accept variables `{:;varname:}`
Example Script:
```python
def main(params=None):
schema = globals().get('__NEUTRAL_SCHEMA__')
return {
"data": {
"varname": "Hello from Python!"
}
}
```
`__NEUTRAL_SCHEMA__` (requires `"schema": true` in object) is read-only for accessing the schema. Access to `__NEUTRAL_SCHEMA__` can be slow, it is faster to use parameters.
It must return a dictionary where the variables are set in the format:
```text
{
"data": {
"varname": "value",
"arrname: {
"key": "value"
}
}
}
```
The variables are set in the template as "locals" `{:;local::varname:}`
Example for the previous script:
```html
{:obj; { "file": "script.py" } >>
{:;local::varname:}
:}
```
Output:
```html
Hello from Python!
```
We can define a template in the object, in the latter case they are summed, first the template defined in the object will be shown and then the inline one.
Modifiers:
----------
```html
{:^obj; ... :}
{:+obj; ... :}
```
### Modifier: ^ (upline)
Removes previous whitespaces.
### Modifier: + (scope)
For more details about the "+" see "modifiers".
No flags
--------
Examples
--------
Basic usage with file:
```html
{:obj; objfile.json :}
```
Inline configuration with parameters:
```html
{:obj;
{
"file": "scripts/hello.py",
"params": {
"name": "World"
}
}
:}
{:obj;
{
"file": "scripts/hello.py",
"params": {
"name": "{:;varname:}"
}
}
:}
```
Using template with script output:
```html
{:obj;
{
"file": "scripts/data.py",
"template": "templates/view.ntpl"
}
:}
```
Limitations
------------
Python is slow and executing Python as a subprocess is even slower, use "{:cache;" when possible.
It is not the same to use "obj" to replace multiple variables than to, for example, create a complete form, in the first case performance will be affected until it is unacceptable, in the second case the loss is likely not noticeable.
---
