如何重定向/显示控制台输出(包括我在程序内部打印的输出),使其显示在Dash应用程序中(用户看到的屏幕上)?
答案 0 :(得分:1)
我没有找到Dash直接读取控制台输出的方法,因此我使用了一种使用文本文件的解决方法。 以下是示例代码,该示例代码将控制台输出的最后20行打印到iframe(以保持换行符的作用,这些行不显示在其他text / div组件中):
import dash_core_components as dcc
import dash_html_components as html
import dash
import sys
f = open('out.txt', 'w')
f.close()
app = dash.Dash()
app.layout = html.Div([
dcc.Interval(id='interval1', interval=1 * 1000,
n_intervals=0),
dcc.Interval(id='interval2', interval=5 * 1000,
n_intervals=0),
html.H1(id='div-out', children=''),
html.Iframe(id='console-out',srcDoc='',style={'width':
'100%','height':400})
])
@app.callback(dash.dependencies.Output('div-out',
'children'),
[dash.dependencies.Input('interval1', 'n_intervals')])
def update_interval(n):
orig_stdout = sys.stdout
f = open('out.txt', 'a')
sys.stdout = f
print 'Intervals Passed: ' + str(n)
sys.stdout = orig_stdout
f.close()
return 'Intervals Passed: ' + str(n)
@app.callback(dash.dependencies.Output('console-out',
'srcDoc'),
[dash.dependencies.Input('interval2', 'n_intervals')])
def update_output(n):
file = open('out.txt', 'r')
data=''
lines = file.readlines()
if lines.__len__()<=20:
last_lines=lines
else:
last_lines = lines[-20:]
for line in last_lines:
data=data+line + '<BR>'
file.close()
return data
app.run_server(debug=False, port=8050)
答案 1 :(得分:0)
执行此操作的一种可能方法是将其提供为Dash Core Component Text Area的value属性的输入。如果它是字符串,这应该可以工作。
答案 2 :(得分:0)
创建一个 custom LoggerHandler,并使用 dcc.Interval
进行刷新。
import dash_core_components as dcc
import dash_html_components as html
from dash.dependencies import Input, Output
import dash
import logging
class DashLoggerHandler(logging.StreamHandler):
def __init__(self):
logging.StreamHandler.__init__(self)
self.queue = []
def emit(self, record):
msg = self.format(record)
self.queue.append(msg)
logger = logging.getLogger()
logger.setLevel(logging.DEBUG)
dashLoggerHandler = DashLoggerHandler()
logger.addHandler(dashLoggerHandler)
app = dash.Dash()
app.layout = html.Div([
dcc.Interval(id='interval1', interval=5 * 1000, n_intervals=0),
html.H1(id='div-out', children='Log'),
html.Iframe(id='console-out',srcDoc='',style={'width': '100%','height':400})
])
@app.callback(
Output('console-out', 'srcDoc'),
Input('interval1', 'n_intervals'))
def update_output(n):
return ('\n'.join(dashLoggerHandler.queue)).replace('\n', '<BR>')
app.run_server(debug=False, port=8050)