Matplot 图像（从 PHP 执行 python）到 png 或 sys.stdout

Question

I'm trying to save matplot image by executing my_task.py from php-script at localhost.

my_task.py

    # do this before importing pylab or pyplot
    import matplotlib
    matplotlib.use('Agg')
    import matplotlib.pyplot as plt
    fig = plt.figure()
    ax = fig.add_subplot(111)
    ax.plot([1,2,3])
    #fig.savefig('/var/www/html/test.png') # or relative path ('test.png') - Here I have an error - filename_or_obj = open(filename_or_obj, 'wb') IOError: [Errno 13] Permission denied: '/var/www/html/test.png'
    print "Hello<br>"
    import sys
    fig.savefig(sys.stdout, type='png')

If I'm trying fig.savefig(sys.stdout, type='png') - I'm getting ieroglighs, unreadable symbols, like:

    ‰PNG  IHDR Xљv‚psBIT|d€ pHYsaaЁ?§i IDATxњмЭ}lЦхЅяс'([О)xЊДrм™r°fБШкђўмЂШ ўђўЁґCV2n„QПшi9•№33ШЩЌ=ћeвNpЭI=‰їљ%PІЪiЎwм¤МЙ офtМЦ#ЗZЫ^ї?>gQn ґЧчєy>’&хZ/|5!qЇлуюѕ?#b±XI’$IЉѓ‘Q
    ђ$I’”>, ’$I’вЖ"I’$)n, ’$I’вЖ"I’$)n, ’$I’вЖ"I’$)n, ’$I’вЖ"I’$)n, ’$I’вЖ"I’$)n, ’$I’вЖ"I’$)n, ’$I’вЖ"I’$)n, ’$I’вЖ"I’$)n, ’$I’вЖ"I’$)n, ’$I’вЖ"I’$)n, ’$I’вЖ"I’$)n, ’$I’вЖ"I’$)n, ’$I’вЖ"I’$)n, ’$I’вЖ"I’$)n, ’$I’вЖ"I’$)n, ’$I’вЖ"I’$)n, 
    ’$I’вЖ"I’$)n, ’$I’вЖ"I’$)n, ’$I’вЖ"I’$)n, ’$I’вЖ"I’$)n, ’$I’вЖ"I’$)n, ’$I’вЖ"I’$)n, ’$I’вЖ"I’$)n, ’$I’вЖ"I’$)n, ’$I’вЖ"I’$)n, зрпяюп<рАЊ?ћїьЛїdмШ±ЬuЧ]јьтЛѓzясгЗyфСG№цЪkЙИИа®»овхЧ_жФ’$IRb»2к‰кдЙ“ЬpГ ,]є”їщ›

But If I try fig.savefig('/var/www/html/test.png') or relative path ('test.png') I have an error:

    filename_or_obj = open(filename_or_obj, 'wb')
    IOError: [Errno 13] Permission denied: '/var/www/html/test.png'

Please, help me with formatting to png or with rights to overcome permissions! How to do it - right formatting to png or giving rights to overcome permissions?

Here is php-code:

  <?php
          $pytask = 'python py/my_task.py';
          echo "<br>" .$pytask,"<br>";
          $command = escapeshellcmd($pytask);
          $output = shell_exec($command);
          echo "<p>",$output,"</p>";
          echo '<p><img src="/PyPlots/test.png" class="img-responsive img-thumbnail" alt="Куыгде"/></p>';

  ?>

Addition: when I tried in php this:

          header("Content-type: image/png");

I received another error: The image " http://localhost/test.php " cannot be displayed because it contains errors

Answer 1

This is a late reply, but hopefully it might still help someone.

See your code. You have 'commas' and not 'dots'

Change: echo "<br>" .$pytask,"<br>"; with: echo "<br>" .$pytask."<br>";

Change: echo "<p>",$output,"</p>"; with: echo "<p>".$output."</p>";

If you have access to your system, see errors (on apache) /var/log/apache2/error.log . It can help you.