getting_start

Getting start for development
1. create a new conda environment by only specifying the name and python=3.6
2. activate the environment
3. pip install -r requirements.txt
4. python app.py
5. In browser, type localhost:8050 to use the tool
6. If pytesseract reports "cannot find tesseract", you will have to install tesseract to your computer manually
	In linux system, type the following commands in terminal:
		sudo apt-get update
		sudo apt-get install tesseract-ocr
		sudo apt-get install libtesseract-dev



Deploy to Heroku
	Preparing for deployment
	1. make sure app.py, requirements.txt are in the same folder
	2. make sure you have server=app.server in your app.py code
	3. css, favicon files should be put under /assets/ folder
	4. make sure gunicorn is included in your requirements.txt, otherwise run "pip install gunicorn" and then do "pip freeze >requirement.txt"
	5. check https://dash.plot.ly/deployment for guidance
	6. create a file named "Procfile" and put "web: gunicorn app:server"
	7. create a file named Aptfile and put the following two lines inside
		tesseract-ocr
		tesseract-ocr-eng

	Deployment steps:

	If this is a new deployment to a new app, first create the app and then config multi-buildpacks and environment variables. If this is to update an existing deployment, you should skip step 1,2,3

	1. [New deployment only] First create the app. In cmd, 
		$ heroku create my-dash-app # change my-dash-app to a unique name
	2. [New deployment only] [Critical!!] config buildpacks. The app requires python and tesseract. So it is required to do multiple buildpacks
		# heroku buildpacks:set heroku/python
		# heroku buildpacks:add --index 1 https://github.com/heroku/heroku-buildpack-apt

		Note that this can also be done in the web gui. To do so, in the dashboard.heroku.com/apps/your-app-name, in setting, click "Add buildpack" and type the "https://github.com/heroku/heroku-buildpack-apt" into the Buildpack URL

	3. [New deployment only] Set heroku config variable
		$ heroku config:set TESSDATA_PREFIX=/app/.apt/usr/share/tesseract-ocr/4.00/tessdata

	   Note that this can also be done in the web gui. To do so, in the dashboard.heroku.com/apps/your-app-name, in setting, click "Reveal Config Vars" and add key "TESSDATA_PREFIX" and value "/app/.apt/usr/share/tesseract-ocr/4.00/tessdata".

	   Also note that this is tested in heroku-18. In other environment, the path might be subject to change.

	   for more information, please refer to
		https://github.com/kevin1061517/python-deploy-Tesseract-OCR-to-Heroku
	   and
		https://stackoverflow.com/questions/53363547/how-to-deploy-pytesseract-to-heroku

	4. [Updating existing app only] make sure you are in the correct app
		$ heroku git:remote -a your-app-name

	5. make sure the Aptfile file is in the folder and contain the correct information
	   make sure the requirement.txt file is in the folder
	   make sure the Procfile file is in the folder and contain the correct information


	6. check what is changed
		$ git status

	7. add file and commit
		$ git add .
		$ git commit -m "your message"

	8. push and build
		$ git push heroku master