将数组 object 从 PHP 传递到 Python

Question

. Answers to this question are eligible for a +50 reputation bounty. Jessen Jie is looking for an :

Im in a middle of essay and need help about this.. so i make the bounty on this. How to solve it?

This is my code so far

    $dataraw = $_SESSION['image'];
    $datagambar = json_encode($dataraw);

    echo '<pre>';
    print_r($dataraw);
    echo '</pre>';

    print($escaped_json);

    $type1 = gettype($dataraw);
    print($type1);

    $type2 = gettype($datagambar);
    print($type2);

This is $dataraw output, the type is array

Array
(
    [0] => Array
        (
            [FileName] => 20221227_202035.jpg
            [Model] => SM-A528B
            [Longitude] => 106.904251
            [Latitude] => -6.167665
        )

    [1] => Array
        (
            [FileName] => 20221227_202157.jpg
            [Model] => SM-A528B
            [Longitude] => 106.9042428
            [Latitude] => -6.1676580997222
        )

)

This is $datagambar output, the type is string

[{"FileName":"20221227_202035.jpg","Model":"SM-A528B","Longitude":106.904251,"Latitude":-6.167665},{"FileName":"20221227_202157.jpg","Model":"SM-A528B","Longitude":106.9042428,"Latitude":-6.167658099722223}]

Pass to python

echo shell_exec("D:\Anaconda\python.exe D:/xampp/htdocs/Klasifikasi_KNN/admin/test.py $datagambar");

This is my python test.py

json_list = []
escaped_json1 = sys.argv[1]

# this is working but its only a string of array json
# print(escaped_json1) 
# this is working but its only a string of array json

json_list.append(json.loads(escaped_json1))
parsed_data = json.loads(escaped_json1) 
print(json_list)
print(parsed_data)

When i do print(escaped_json1) it display a string of array json from php($datagambar).

python output:

Hello world has been called [{"FileName":"20221227_202035.jpg","Model":"SM-A528B","Longitude":106.904251,"Latitude":-6.167665},{"FileName":"20221227_202157.jpg","Model":"SM-A528B","Longitude":106.9042428,"Latitude":-6.167658099722223}]

I use apache as my server with phpmyadmin and anaconda.

T tried using print(type(escapedjson1)) or print(type(escapedjson1)) but it doesn't display the type

json.loads didn't change the type of data to python array

How to loads it and make the string array into a variable array so i can call it and convert it to dataframe?.

Answer 1

You just need to enclose in single quotes the argument to python:

shell_exec("python3 test.py '$json'");

Example

file.php

$data =
[
    [
        "FileName" => "20221227_202035.jpg",
        "Model" => "27_202035.jpg",
        "Longitude" => 106.90425,
        "Latitude" => 106.90425
    ],
    [
        "FileName" => "20221227_202157.jpg",
        "Model" => "SM-A528B",
        "Longitude" => 106.9042428,
        "Latitude" => -6.1676580997222
    ]
];

$json = json_encode($data);

// note: arg '$json' is single-quoted
echo shell_exec("python3 test.py '$json'");

test.py

import sys
import json
from pandas import json_normalize

data = sys.argv[1]

dict = json.loads(data)
df2 = json_normalize(dict) 

print(df2)

Output

              FileName     Model   Longitude  Latitude
0  20221227_202035.jpg  SM-A528B  106.904251 -6.167665
1  20221227_202157.jpg  SM-A528B  106.904243 -6.167658

See: Escaping double qoutes when sending JSON as argument in python program

Answer 2

Update: A Completely different approach

There is a difficulty with the PHP script JSON-encoding a structure to produce a JSON string and then passing it as a command line argument since the string needs to be placed in double quotes because there can be embedded spaces in the encoded string. But the string itself can contain double quotes as start of string characters and within such a string. Confused? Who wouldn't be?

There is no problem however with writing such a string to a file and having the Python program read it in and decode it. But we don't want to have to deal with temporary files. So the solution is to pipe the data to the Python program where it can then be read in as stdin

Let's assume your array looks like:

$arr =
[
    [
        "FileName" => "\"\\  \nRon's20221227_202035.jpg",
        "Model" => "27_202035.jpg",
        "Longitude" => 106.90425,
        "Latitude" => 106.90425
    ],
    [
        "FileName" => "20221227_202157.jpg",
        "Model" => "SM-A528B",
        "Longitude" => 106.9042428,
        "Latitude" => -6.1676580997222
    ]
];

Note that I have modified your example slightly so that the first FileName field contains a " character, a ' character, an escape sequence \n representing the newline character and finally some spaces. Although your example does not contain these characters or some other escape sequence, I would like to be able to handle such a condition should it arise. This solution should work with such input.

PHP File

<?php
$arr =
[
    [
        "FileName" => "\"\\  \nRon's20221227_202035.jpg",
        "Model" => "27_202035.jpg",
        "Longitude" => 106.90425,
        "Latitude" => 106.90425
    ],
    [
        "FileName" => "20221227_202157.jpg",
        "Model" => "SM-A528B",
        "Longitude" => 106.9042428,
        "Latitude" => -6.1676580997222
    ]
];

// Encode string as JSON:
$json = json_encode($arr);

// Pipe the JSON string to the Python process's stdin and
// read the result from its stdout:
$descriptorspec = array(
   0 => array("pipe", "r"),  // stdin is a pipe that the child will read from
   1 => array("pipe", "w")   // stdout is a pipe that the child will write to
);
$process = proc_open("python3 test.py", $descriptorspec, $pipes);

// Pipe the input for the Python program and close the pipe:
fwrite($pipes[0], $json);
fclose($pipes[0]);

// Read the result from the Python program and close its pipe
$result = stream_get_contents($pipes[1]);
fclose($pipes[1]);

# Now that we have closed the pipe, we can close the process:
$return_code = proc_close($process);

echo $result;

test.py

import json
import sys

# Read from stdin:
json_string = sys.stdin.read()
arr = json.loads(json_string)
# print each dictionary of the array:
for d in arr:
    print(d)

Prints:

{'FileName': '"\\  \nRon\'s20221227_202035.jpg', 'Model': '27_202035.jpg', 'Longitude': 106.90425, 'Latitude': 106.90425}
{'FileName': '20221227_202157.jpg', 'Model': 'SM-A528B', 'Longitude': 106.9042428, 'Latitude': -6.1676580997222}