VCards in python+flask

app.py

# Simplistic example using send_file to send the contents generated in the service

@app.route("/vcard/<href_token>")
def get_person_vcard(request: requests.HTTPRequest, href_token: str):
    vcard_stream = self.vcard_service.get_vcard(b64decode(href_token.encode('UTF-8')).decode('UTF-8'))
    return send_file(vcard_stream, mimetype='text/vcard')

model.py

# I used pydantic to create models of the fields I was interestd in including in the vcard:

from enum import Enum
from typing import List, Optional
from pydantic import BaseModel


class VCardPhoneType(Enum):
    text = "text"
    voice = "voice"
    fax = "fax"
    cell = "cell"
    pager = "pager"
    textphone = "textphone"  # TDD


class VCardPhone(BaseModel):
    types: List[VCardPhoneType]
    value: str


class VCard(BaseModel):
    last_name: str
    name_extras: List[str] = []
    display_name: str
    titles: List[str] = []
    departments: List[str] = []
    email: Optional[str]
    phones: List[VCardPhone] = []

service.py

# I created a VCardService that is responsible for querying data and creating a model instance. (This is only a portion of
# the implementation, just to show the VCard parts:
from flask import render_template
from io import BytesIO

class VCardService:
    @property
    def request_is_authenticated(self):
        session = self.injector.get(LocalProxy)
        return bool(session.get("uwnetid"))

      def get_vcard(self, href: str) -> BytesIO:
        person = self.query_person(href)  # Pseudocode; cutting contextual stuff unrelated to the problem
        name_parts = list(reversed(person.display_name.split()))
        vcard = VCard.construct(
            last_name=name_parts.pop(0),
            name_extras=name_parts,
            display_name=person.display_name,
        )
        self.do_other_work(vcard, person)  # Pseudocode
        # Render the vcard template with the user's data,
        content = render_template('vcard.vcf.jinja2', **vcard.dict())
        # Remove all the extra lines that jinja2 leaves in there. (ugh.)
        content = '\n'.join(filter(lambda line: bool(line.strip()), content.split('\n')))
        # Create a file-like object to send to the client
        file_ = BytesIO()
        file_.write(content.encode('UTF-8'))
        file_.seek(0)

        return file_

template.vcf.jinja2

{#
    Do not adhere to conventional indendation in this file.
    Line breaks for long lines must only happen _inside_ jinja blocks.
    field must be on a single line, with no indents. This will
    still leave lots of vacant lines that should be cleaned up.
    Specification: https://tools.ietf.org/html/rfc6350
    Model: husky_directory.models.vcard.VCard
#}
BEGIN:VCARD
{# woofington;dawg;husky #}
N:{{ last_name }};{% for e in name_extras %}{{ e }}{{
        ';' if not loop.last else '' }}
{% endfor %}
{# Husky Dawg Woofington #}
FN:{{ display_name }}
{% for title in titles %}
TITLE:{{ title }}
{% endfor %}
{% for dept in departments %}
ORG:{{ dept }}
{% endfor %}
{% if not email is blank %}
{# EMAIL;type=INTERNET;type=WORK:[email protected] #}
EMAIL;type=INTERNET;type=WORK:{{ email }}
{% endif %}
{% for phone in phones %}
{# TEL;type=voice,pager:5558675309 #}
TEL;type={% for pt in phone['types'] %}{ {{ pt }}{{
        ',' if not loop.last else '' }}:{{ phone['value'] }}
{% endfor %} {# pt in phone['types'] #}
{% endfor %} {# phone in phones #}
END:VCARD