Use background tasks for file operations.

app/corpora/background_tasks.py

@@ -0,0 +1,25 @@
+from app.models import Corpus, CorpusFile
+
+
+def delete_corpus_(app, corpus_id):
+    with app.app_context():
+        corpus = Corpus.query.filter_by(id=corpus_id).first()
+        if corpus is None:
+            raise Exception('Corpus {} not found!'.format(corpus_id))
+        corpus.delete()
+
+
+def delete_corpus_file_(app, corpus_file_id):
+    with app.app_context():
+        corpus_file = CorpusFile.query.filter_by(id=corpus_file_id).first()
+        if corpus_file is None:
+            raise Exception('Corpus file {} not found!'.format(corpus_file_id))
+        corpus_file.delete()
+
+
+def edit_corpus_file_(app, corpus_file_id):
+    with app.app_context():
+        corpus_file = CorpusFile.query.filter_by(id=corpus_file_id).first()
+        if corpus_file is None:
+            raise Exception('Corpus file {} not found!'.format(corpus_file_id))
+        corpus_file.insert_metadata()

app/corpora/views.py

@@ -1,11 +1,12 @@
 from app import db
 from app.models import Corpus, CorpusFile
-from app.utils import background_prepare_corpus_file
 from flask import (abort, current_app, flash, redirect, request,
                    render_template, url_for, send_from_directory)
 from flask_login import current_user, login_required
 from werkzeug.utils import secure_filename
 from . import corpora
+from .background_tasks import (delete_corpus_, delete_corpus_file_,
+                               edit_corpus_file_)
 from .forms import (AddCorpusFileForm, AddCorpusForm, EditCorpusFileForm,
                     QueryDownloadForm, QueryForm)
 import os
@@ -80,29 +81,16 @@ def corpus_analysis(corpus_id):
                            title='Corpus: {}'.format(corpus.title))
 
 
-@corpora.route('/<int:corpus_id>/prepare')
-@login_required
-def prepare_corpus(corpus_id):
-    corpus = Corpus.query.get_or_404(corpus_id)
-    if not (corpus.creator == current_user or current_user.is_administrator()):
-        abort(403)
-    if len(corpus.files.all()) > 0:
-        corpus.status = 'preparable'
-        db.session.commit()
-        flash('Corpus marked for preparation!')
-    else:
-        flash('Can not prepare corpus, please add corpus file(s).')
-    return redirect(url_for('corpora.corpus', corpus_id=corpus_id))
-
-
 @corpora.route('/<int:corpus_id>/delete')
 @login_required
 def delete_corpus(corpus_id):
     corpus = Corpus.query.get_or_404(corpus_id)
     if not (corpus.creator == current_user or current_user.is_administrator()):
         abort(403)
-    delete_thread = threading.Thread(corpus.delete())
+    thread = threading.Thread(target=delete_corpus_,
-    delete_thread.start()
+                              args=(current_app._get_current_object(),
+                                    corpus.id))
+    thread.start()
     flash('Corpus deleted!')
     return redirect(url_for('main.dashboard'))
 
@@ -132,11 +120,10 @@ def add_corpus_file(corpus_id):
                                  title=add_corpus_file_form.title.data)
         db.session.add(corpus_file)
         db.session.commit()
-        background_thread = threading.Thread(
+        thread = threading.Thread(target=edit_corpus_file_,
-            args=(current_app._get_current_object(), corpus_file.id),
+                                  args=(current_app._get_current_object(),
-            target=background_prepare_corpus_file
+                                        corpus_file.id))
-        )
+        thread.start()
-        background_thread.start()
         flash('Corpus file added!')
         return redirect(url_for('corpora.corpus', corpus_id=corpus_id))
     return render_template('corpora/add_corpus_file.html.j2',
@@ -153,8 +140,10 @@ def delete_corpus_file(corpus_id, corpus_file_id):
     if not (corpus_file.corpus.creator == current_user
             or current_user.is_administrator()):
         abort(403)
-    delete_thread = threading.Thread(corpus_file.delete())
+    thread = threading.Thread(target=delete_corpus_file_,
-    delete_thread.start()
+                              args=(current_app._get_current_object(),
+                                    corpus_file.id))
+    thread.start()
     flash('Corpus file deleted!')
     return redirect(url_for('corpora.corpus', corpus_id=corpus_id))
 
@@ -188,10 +177,28 @@ def edit_corpus_file(corpus_id, corpus_file_id):
         corpus_file.author = edit_corpus_file_form.author.data
         corpus_file.publishing_year = edit_corpus_file_form.publishing_year.data
         corpus_file.title = edit_corpus_file_form.title.data
-        corpus_file.insert_metadata()
         db.session.commit()
+        thread = threading.Thread(target=edit_corpus_file_,
+                                  args=(current_app._get_current_object(),
+                                        corpus_file.id))
+        thread.start()
         flash('Corpus file edited!')
         return redirect(url_for('corpora.corpus', corpus_id=corpus_id))
     return render_template('corpora/edit_corpus_file.html.j2',
                            edit_corpus_file_form=edit_corpus_file_form,
                            corpus_file=corpus_file, title='Edit corpus file')
+
+
+@corpora.route('/<int:corpus_id>/prepare')
+@login_required
+def prepare_corpus(corpus_id):
+    corpus = Corpus.query.get_or_404(corpus_id)
+    if not (corpus.creator == current_user or current_user.is_administrator()):
+        abort(403)
+    if len(corpus.files.all()) > 0:
+        corpus.status = 'preparable'
+        db.session.commit()
+        flash('Corpus marked for preparation!')
+    else:
+        flash('Can not prepare corpus, please add corpus file(s).')
+    return redirect(url_for('corpora.corpus', corpus_id=corpus_id))

app/utils.py

@@ -55,18 +55,3 @@ def background_delete_job(app, job_id):
                 job.delete_job()
                 deleted = True
         logger.warning('Loop has ended.')
-
-
-def background_delete_corpus(app, corpus_id):
-    logger = logging.getLogger(__name__)
-    with app.app_context():
-        logger.warning('Called by delete_thread.')
-        logger.warning('Corpus id is: {}.'.format(corpus_id))
-        corpus = Corpus.query.filter_by(id=corpus_id).first()
-        corpus.delete()
-
-
-def background_prepare_corpus_file(app, corpus_file_id):
-    with app.app_context():
-        corpus_file = CorpusFile.query.filter_by(id=corpus_file_id).first()
-        corpus_file.insert_metadata()