From 2831ac55c47a786c021963f8415793dc729ca00b Mon Sep 17 00:00:00 2001
From: Oliver Walters <oliver.henry.walters@gmail.com>
Date: Thu, 27 Jun 2019 22:15:58 +1000
Subject: [PATCH] Link to download a BOM template file

---
 InvenTree/InvenTree/helpers.py                | 28 +++++++++++++++++++
 InvenTree/part/forms.py                       |  1 +
 InvenTree/part/templates/part/bom_upload.html | 13 +++++++++
 InvenTree/part/urls.py                        |  3 ++
 InvenTree/part/views.py                       | 14 +++++++++-
 5 files changed, 58 insertions(+), 1 deletion(-)
 create mode 100644 InvenTree/part/templates/part/bom_upload.html

diff --git a/InvenTree/InvenTree/helpers.py b/InvenTree/InvenTree/helpers.py
index ddb4e35fee..2c2f74fde6 100644
--- a/InvenTree/InvenTree/helpers.py
+++ b/InvenTree/InvenTree/helpers.py
@@ -6,6 +6,7 @@ import io
 import json
 import os.path
 from PIL import Image
+import tablib
 
 from wsgiref.util import FileWrapper
 from django.http import StreamingHttpResponse
@@ -91,6 +92,33 @@ def MakeBarcode(object_type, object_id, object_url, data={}):
     return json.dumps(data, sort_keys=True)
 
 
+def IsValidSpreadsheetFormat(fmt):
+    """ Test if a file format specifier is in the valid list of spreadsheet file formats """
+
+    return fmt.lower() in ['csv', 'xls', 'xlsx', 'tsv']
+
+
+def MakeBomTemplate(fmt):
+    """ Generate a Bill of Materials upload template file (for user download) """
+
+    if not IsValidSpreadsheetFormat(fmt):
+        fmt = 'csv'
+
+    fields = [
+        'Part',
+        'Quantity',
+        'Overage',
+        'Reference',
+        'Notes'
+    ]
+
+    data = tablib.Dataset(headers=fields).export(fmt)
+
+    filename = 'InvenTree_BOM_Template.' + fmt
+
+    return DownloadFile(data, filename)
+
+
 def DownloadFile(data, filename, content_type='application/text'):
     """ Create a dynamic file for the user to download.
     
diff --git a/InvenTree/part/forms.py b/InvenTree/part/forms.py
index 4512859828..8c90de9dd2 100644
--- a/InvenTree/part/forms.py
+++ b/InvenTree/part/forms.py
@@ -8,6 +8,7 @@ from __future__ import unicode_literals
 from InvenTree.forms import HelperForm
 
 from django import forms
+from django.core.validators import MinValueValidator
 
 from .models import Part, PartCategory, PartAttachment
 from .models import BomItem
diff --git a/InvenTree/part/templates/part/bom_upload.html b/InvenTree/part/templates/part/bom_upload.html
new file mode 100644
index 0000000000..b62cbc9c49
--- /dev/null
+++ b/InvenTree/part/templates/part/bom_upload.html
@@ -0,0 +1,13 @@
+{% extends "modal_form.html" %}
+
+{% block pre_form_content %}
+
+{{ block.super }}
+
+<p>Select a BOM file to upload for <b>{{ part.name }} - <i>{{ part.description }}</i></b>.</p>
+
+<p>The BOM file must contain the required named columns as provided in the <a href="/part/bom_template/">BOM Upload Template</a></a></p>
+
+<p>Supported file formats: <i>.csv, .tsv, .xls, .xlsx</i></p>
+
+{% endblock %}
\ No newline at end of file
diff --git a/InvenTree/part/urls.py b/InvenTree/part/urls.py
index a8f5184972..bfb542cb3f 100644
--- a/InvenTree/part/urls.py
+++ b/InvenTree/part/urls.py
@@ -74,6 +74,9 @@ part_urls = [
     # Create a new BOM item
     url(r'^bom/new/?', views.BomItemCreate.as_view(), name='bom-item-create'),
 
+    # Download a BOM upload template
+    url(r'^bom_template/?', views.BomUploadTemplate.as_view(), name='bom-upload-template'),
+
     # Individual part
     url(r'^(?P<pk>\d+)/', include(part_detail_urls)),
 
diff --git a/InvenTree/part/views.py b/InvenTree/part/views.py
index 08e3be79cb..1415547d86 100644
--- a/InvenTree/part/views.py
+++ b/InvenTree/part/views.py
@@ -12,6 +12,7 @@ from django.shortcuts import get_object_or_404
 from django.utils.translation import gettext_lazy as _
 from django.urls import reverse_lazy
 from django.views.generic import DetailView, ListView
+from django.views.generic.edit import FormMixin
 from django.forms.models import model_to_dict
 from django.forms import HiddenInput, CheckboxInput
 
@@ -26,7 +27,7 @@ from . import forms as part_forms
 from InvenTree.views import AjaxView, AjaxCreateView, AjaxUpdateView, AjaxDeleteView
 from InvenTree.views import QRCodeView
 
-from InvenTree.helpers import DownloadFile, str2bool
+from InvenTree.helpers import DownloadFile, str2bool, MakeBomTemplate
 from InvenTree.status_codes import OrderStatus
 
 
@@ -722,6 +723,17 @@ class BomUpload(AjaxView):
         }
 
         return self.renderJsonResponse(request, form, data=data)
+class BomUploadTemplate(AjaxView):
+    """
+    Provide a BOM upload template file for download.
+    - Generates a template file in the provided format e.g. ?format=csv
+    """
+
+    def get(self, request, *args, **kwargs):
+
+        export_format = request.GET.get('format', 'csv')
+
+        return MakeBomTemplate(export_format)
 
 
 class BomDownload(AjaxView):