CODEWITHSUNDEEP
python
user5007670
user5007670

Reputation:

how not to throw an error even for 'None' type?

I am trying to create HTML format (for sending automatic emails)from JSON data I get from an internal database, I am getting the following error for 'None' type,I want to capture 'None' type aswell?how to not throw an error even for 'None' type?

INPUT:-

{'total': 0, 'Resolution': None, 'key': u'CNSSDEBUG-151394', 'summary': u'[Lenovo][NFA344A][Win10] - [QCA6174_9377.WIN.1.0-10366-QCARMTFX86WZ-2] - Undetermined crash root cause'}

CODE:-

........
    for item in jiradb :
        MailBody = MailBody + "<tr>"
        MailBody = MailBody + "<td>" + str(icount) + "</td>"
        print item['key']
        MailBody = MailBody + "<td>" + item['key'].rstrip('\n!') + "</td>"
        MailBody = MailBody + "<td>" + item['summary'].rstrip('\n!') + "</td>"
        MailBody = MailBody + "<td>" + item['Resolution'].rstrip('\n!') + "</td>"
        icount = icount + 1

.......................

Error:-

Traceback (most recent call last):
  File "sns.py", line 217, in <module>
    main()
  File "sns.py", line 215, in main
    sendmail(meta,jiradb,total_no_crashes)
  File "sns.py", line 47, in sendmail
    MailBody = MailBody + "<td>" + item['Resolution'].rstrip('\n!') + "</td>"
AttributeError: 'NoneType' object has no attribute 'rstrip'

Upvotes: 0

Views: 130

Answers (2)

alecxe
alecxe

Reputation: 473813

It might sound like too broad of an answer, but I would suggest to switch to a template engine, like mako or jinja2, instead of trying to manually construct HTML using the string concatenation. You would solve this kind of problem just by using the variable placeholders and built-in or custom filters.

As a bonus, you would get a nice separation of logic (your Python code) and presentation - the generated HTML. A much cleaner and more testable code.

Here is a working sample using jinja2 (created a custom rstrip filter):

from jinja2 import Environment, FileSystemLoader

jiradb = [
    {'total': 0, 'Resolution': None, 'key': u'CNSSDEBUG-151394', 'summary': u'[Lenovo][NFA344A][Win10] - [QCA6174_9377.WIN.1.0-10366-QCARMTFX86WZ-2] - Undetermined crash root cause'},
    {'total': 1, 'Resolution': 'fixed', 'key': u'CNSSDEBUG-151395', 'summary': u'Some other summary'},
]

env = Environment(loader=FileSystemLoader('.'))
env.filters['rstrip'] = lambda value, s: value.rstrip(s) if value else ''

template = env.get_template('index.html')
print(template.render(jiradb=jiradb))

index.html contents:

<table>
    {% for item in jiradb %}
        <tr>
            <td>{{ loop.index }}</td>
            <td>{{ item.key|rstrip("\n!") }}</td>
            <td>{{ item.summary|rstrip("\n!") }}</td>
            <td>{{ item.Resolution|rstrip("\n!") }}</td>
        </tr>
    {% endfor %}
</table>

Prints:

<table>
    <tr>
        <td>1</td>
        <td>CNSSDEBUG-151394</td>
        <td>[Lenovo][NFA344A][Win10] - [QCA6174_9377.WIN.1.0-10366-QCARMTFX86WZ-2] - Undetermined crash root cause</td>
        <td></td>
    </tr>

    <tr>
        <td>2</td>
        <td>CNSSDEBUG-151395</td>
        <td>Some other summary</td>
        <td>fixed</td>
    </tr>
</table>

Upvotes: 4

kdopen
kdopen

Reputation: 8215

Extract each field from the dict using dict.get(key,default) to avoid missing fields, and then use or to cover the None case

For example

item['Resolution'].rstrip('\n!')

becomes

(item.get('Resolution', None) or '').rstrip('\n!')

Then you probably want a helper function

   def get_field(item, field, default=''):
       return (item.get(field, None) or default).rstrip('\n!')

Then your loop is a little cleaner and you are safer from typos

........
    for item in jiradb :
        MailBody = MailBody + "<tr>"
        MailBody = MailBody + "<td>" + str(icount) + "</td>"
        print get_field(item, 'key')
        MailBody = MailBody + "<td>" + get_field(item,'key') + "</td>"
        MailBody = MailBody + "<td>" + get_field(item,'summary') + "</td>"
        MailBody = MailBody + "<td>" + get_field(item,'Resolution') + "</td>"
        icount = icount + 1

Upvotes: 2

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