Showing posts with label book reviews. Show all posts
Showing posts with label book reviews. Show all posts

Monday, December 9, 2013

Book Review: "Instant Flask Web Development" by Ron DuPlain

"Instant Flask Web Development" by Ron DuPlain (Packt Publishing http://www.packtpub.com/flask-web-development/book) is intended to be an introduction to Flask, a lightweight web application framework written in Python and based on the Werkzeug WSGI toolkit and Jinja2 template engine.

The book takes a tutorial style approach, building up an example appointment-management web application using Flask and introducing various features of the framework on the way. As the example application becomes more complicated, additional Python packages are covered which are not part of the Flask framework (for example SQLAlchemy for managing interactions with a database backend, and WTForm for handling form generation and validation) along with various Flask extensions that can be used for more complicated tasks (for example managing user logins and sessions). The final section of the book gives an overview of how to deploy the application in a production environment, using gunicorn (a Python WSGI server) and nginx.

Given its length (just short of 70 pages) the book is quite ambitious in the amount of ground that it attempts to cover, and it's quite impressive how much the author has managed to pack in whilst maintaining a light touch with the material. So while inevitably there is a limit to the level of detail that can be fitted in, there are some excellent and concise overviews of many of the topics that could act as excellent starting points for more experienced developers (for me the section on SQLAlchemy is a particular highlight). Overall the pacing of the book is also quite sprightly and conveys a sense of how quickly and easily Flask could be used to build a web application from scratch.

The flipside of the book's brevity is that it cannot possibly contain everything that a developer needs to know (although this is mitigated to some extent by extensive references to online documentation and resources). In this regard it is really more a showcase for Flask, and is best viewed as a good starting point for someone wishing to quickly get up to speed with the framework's potential. I'd also question how suitable this is for newcomers to either Python, or to web programming in general - I felt that some of the concepts and example code (for example the sudden appearance of a feature implemented using Ajax) might be a bit of a stretch for a novice. Also there are some occasional frustrating glitches in the text and example code which meant it took a bit of additional reading and debugging in places to get the example application working in practice.

In summary then: I'd recommend this book as a good starting point for developers who already have some familiarity with web application development, and who are interested in a quick introduction to the key components of Flask and how they're used - with the caveat that you will most likely have to refer to other resources to get the most out of it.

Disclosure: a free e-copy of this book was received from the publisher for review purposes; this review has also been submitted to Amazon. The opinions expressed here are entirely my own.

Wednesday, July 27, 2011

Book review: “Python Testing Cookbook” by Greg L. Turnquist

Disclosure: a free e-copy of this book was received from the publisher for review purposes. The opinions expressed here are entirely my own; a copy of this review has also been posted at Amazon.

Greg L. Turnquist’s “Python Testing Cookbook” explores automated testing at all levels, with the intention of providing the reader with the knowledge needed to implement testing using Python tools to improve software quality. To this end the book presents over 70 “recipes” in its nine chapters (ranging from the basics of unit testing, through test suites, user acceptance and web application testing, continuous integration, and methods for smoke- and load-testing), covering both tools for testing Python, and Python tools for testing. It also delivers advice about how to get the most from automated testing, which is as much an art as a science.

The first three chapters introduce the fundamentals: writing, organising and running unit tests, comprehensively covering unittest (Python’s built-in unit testing library), nose (a versatile tool for discovering, running and reporting tests) and doctest (which turns Python docstrings into testable code – a sample of this chapter can be downloaded from http://www.packtpub.com/python-testing-cookbook/book). Having established a solid foundation, subsequent chapters look at increasingly broader levels of automated testing using the appropriate relevant Python tools: for example, the “lettuce” and “should_DSL” libraries for “behaviour driven development” (an extension of “test driven development” which aims to produce human-readable test cases and reports), and the “Pyccuracy” and “Robot” frameworks for end-user acceptance testing of web applications. Later chapters cover higher level concepts and tools, such as using nose to hook Python tests into “continuous integration” servers (both Jenkins and TeamCity are covered in detail), and assessing test coverage using the “coverage” tool (both as a metric, and to identify areas that need more tests). A detailed chapter on smoke- and load-testing includes practical advice on developing multiple test suites for different scenarios, and methods for stress-testing (for example, by capturing and replaying real world data) to discover weaknesses in a system before going to production. The final chapter distils the author’s experience into general advice on making testing a successful part of your code development methodology, both for new and legacy projects.

There’s a lot of good stuff in this book: the initial chapters on unittest and nose are particularly strong, and I can imagine returning to these in future as a reference. There is also a lot of excellent and hard-won practical advice from the author’s own experience – not only in these early chapters but throughout the book – which is consistently valuable (in this regard the final chapter is a real highlight and could easily stand alone – I will definitely be re-reading it soon). Elsewhere the various tools and topics are presented clearly with plenty of useful detail, and in some cases have demystified things that I’d always assumed were quite esoteric and difficult to do (nose in particular was a revelation to me, but also setting up continuous integration servers and measuring test coverage).

There are a few disappointments: the section on mock objects left me feeling baffled as to how to actually implement them in practice – a shame as it was something that I’d looked forward to learning. I’d also have liked something about approaches for handling difficult testing scenarios such as software which interacts with the file system or with large files – a few hints here would have been invaluable for me. There are typos in some commands and code in a few recipes (e.g. for nose), which meant I had to look up the correct syntax elsewhere – perhaps not so bad, but annoying (especially in a cookbook) – and since the recipes themselves aren’t numbered, this sometimes made it difficult to navigate between them.

However these are fairly minor quibbles, and in conclusion I was impressed with both the breadth of material covered by the book and the level of detail for many topics. Moreover I enjoyed reading it and was often left feeling excited at the prospect of being able to apply the ideas to my own projects, which is I think was one of the author’s aims (and no mean feat for a technical book). I think that the combination of the detail together with the author’s practical advice make this book both an excellent introduction to testing with Python, and a valuable resource to refer back to subsequently.

(Addendum: Greg Turnquist's blog about the book can be found at http://pythontestingcookbook.posterous.com/ and features some interesting supplementary material.)

Sunday, April 3, 2011

Book review: "Python 2.6 Text Processing: Beginner’s Guide" by Jeff McNeil

Jeff McNeil’s “Python 2.6 Text Processing: Beginner’s Guide” is a practical introduction to a wide range of methods for reading, processing and writing textual data from a variety of structured and unstructured data formats. Aimed primarily at novice Python programmers who have some elementary knowledge of the language basics but without prior experience in text processing, the book offers hands-on examples for each of the techniques it discusses – ranging from Python’s built-in libraries for handling strings, regular expressions, and formats such as JSON, XML and HTML, through to more advanced topics such as parsing custom grammars, and efficiently searching large text archives. In addition it contains a great deal of general supporting material on working with Python, including installing packages and third-party libraries, and working with Python 3.

The first three chapters lay the foundations, covering a number of Python basics including a crash course in file and URL I/O, and the essentials of Python’s built-in string handling functions. Useful background topics – such as installing packages with easy_install, and using virtualenv – are also introduced here. (A sample of the first chapter can be freely downloaded from the book’s website at https://www.packtpub.com/python-2-6-text-processing-beginners-guide/book). The next three cover: using the standard library to work with simple structured data formats (delimited “CSV” data, “ini”-style configuration files, and JSON-formatted data); working with Python regular expressions (a stand out chapter for me); and handling structured markup (specifically, XML and HTML). Subsequent chapters on using the Mako templating package (the default system for the Pylons web framework) to generate emails and web pages, and on writing more advanced data formats (PDF, Excel and OpenDocument), are separated by an excellent overview of understanding and working with Unicode, encodings and application internationalization (“i18n”).

The remaining two chapters cover more advanced topics, with some good background theory supplementing the practical examples: using the PyParsing package to create parsers for custom grammars (with a brief nod to the basics of natural language processing using the Natural Language Toolkit, NLTK); and the Nucular package for indexing large quantities of textual data (not necessarily just plain text) to enable highly efficient searching. Finally, an appendix offers a grab-bag of general Python resources, references to some more advanced text processing tools (such as Apache’s Lucene/Solr), and an excellent overview of the differences between Python 2 and 3 (including a hands-on example of migrating code from 2 to 3).

The book covers a lot of ground and moves fairly quickly; however it adopts a largely successful hands-on approach, engaging the reader with working examples at each stage to illustrate the key points, and this certainly helped me keep up. I was also impressed by the clear and concise quality of code in the examples, and the very natural way that general Python concepts and principles – generators, duck typing, packaging and so on – were introduced as asides. (One very minor criticism is that the layout of the example code could have been improved, as the indentation levels weren’t always immediately obvious to me.) Aside from a surprisingly unsatisfying chapter on structured markup (reluctantly, I would recommend looking elsewhere for an introduction to XML processing with Python) and a few niggling typos, there’s a lot of excellent material in this book, and the author has a knack for presenting some tricky concepts in a deceptively easy-to-understand manner. I think that the chapter on regular expressions is possibly one of the best introductions to the subject that I’ve ever seen; other chapters on encodings and internationalization, advanced parsing, and indexing and searching were also highlights for me (as was the section on Python 3 in the appendix).

Overall I really enjoyed working through the book and felt I learned a lot. I think it’s fair to say that given the rather ambitious range of techniques presented, in many cases (particularly for the more advanced or specialised topics) that the chapters are inevitably more introductory than definitive in nature: the reader is given enough information to grasp the background concepts and get started, with pointers to external resources to learn more. In conclusion, I think this is a great introduction to a wide range of text processing techniques in Python, both for novice Pythonistas (who will undoubtedly also benefit from the more general Python tips and tricks presented in the book) and more experienced programmers who are looking for a place to start learning about text processing.

Disclosure: a free e-copy of this book was received from the publisher for review purposes; this review has also been submitted to Amazon.

Friday, February 25, 2011

Book review: "Simply SQL" by Rudy Limeback

Rudy Limeback's "Simply SQL" (Sitepoint) is an overview of SQL targeted at web application developers, and intended to fill a gap between the basic "SQL 101"-type tutorials (seemingly compulsory in just about every introductory article or book about web programming) and more advanced texts covering topics which at first glance don't seem so relevant to the straightforward day-to-day requirements of many web applications.

The chapters are grouped into two main sections. The first deals with the details of the SQL language and comprises the bulk of the book. It starts with a short introduction to the SQL commands most commonly needed by web developers to create and modify data within the database (all the usual suspects - CREATE, ALTER, INSERT, UPDATE, DELETE and so on - are quickly dealt with here). The rest of this section focuses on the SELECT command (the one used to retrieve information), with each chapter covering one specific clause - FROM, WHERE, GROUP BY and so on - in quite extensive detail, and illustrated with examples from sample applications.

The second section of the book has three chapters covering some basic database design concepts, specifically SQL data types, relational integrity, and the use of "special structures" (such as tables that refer to themselves) for particular situations. The appendices then outline the basics of using some specific SQL implementations, along with details of the sample applications and scripts used in the main part of the book.

The heavy emphasis on the SELECT statement might seem odd, but it makes a lot of sense in the context of web applications where data is typically read from the database far more than it's written. The detailed examples are also excellent - at times invaluable - for clarifying things like (for example) the nuances of the different types of JOINS, the subtleties of the GROUP BY and HAVING clauses (useful for aggregating data from subsets of rows in conjunction with summing and averaging functions), and the issues with working with time data. I certainly learnt a few things - the GROUP BY clause was completely new to me, as were the distinctions between the FLOAT and DECIMAL data types (DECIMALs are exact - within certain limits - while FLOATs are approximate). I found the brief sections on views, derived tables and subqueries extremely enlightening, as was the discussion of foreign keys in the chapter on relational integrity, and the clear writing style throughout made the book a pleasure to read.

It's important to note that "Simply SQL" is based on the SQL standard, rather than the syntax of specific implementations (although in places it does indicate where there are notable deviations from the standard, particularly for MySQL) - also it doesn't cover any of the programming APIs, so it's not really a reference text (admittedly it doesn't claim to be). However with its clear and detailed explanations it looks like it would be a useful companion to more traditional reference or cookbooks and will definitely reward re-reading - least ways, I'm sure I'll be squeezing plenty more juice out of it in the future. So overall highly recommended.