Category Archives: Books

Review: curl programming

Title: Curl Programming
Author: Dan Gookin
ISBN: 9781704523286
Weight: 181 grams

A book for my library is a book about my library!

Not long ago I discovered that someone had written this book about curl and that someone wasn’t me! (I believe this is a first) Thrilled of course that I could check off this achievement from my list of things I never thought would happen in my life, I was also intrigued and so extremely curious that I simply couldn’t resist ordering myself a copy. The book is dated October 2019, edition 1.0.

I don’t know the author of this book. I didn’t help out. I wasn’t aware of it and I bought my own copy through an online bookstore.

First impressions

It’s very thin! The first page with content is numbered 13 and the last page before the final index is page 110 (6-7 mm thick). Also, as the photo shows somewhat: it’s not a big format book either: 225 x 152 mm. I suppose a positive spin on that could be that it probably fits in a large pocket.

Size comparison with the 2018 printed version of Everything curl.

I’m not the target audience

As the founder of the curl project and my role as lead developer there, I’m not really a good example of whom the author must’ve imagined when he wrote this book. Of course, my own several decades long efforts in documenting curl in hundreds of man pages and the Everything curl book makes me highly biased. When you read me say anything about this book below, you must remember that.

A primary motivation for getting this book was to learn. Not about curl, but how an experienced tech author like Dan teaches curl and libcurl programming, and try to use some of these lessons for my own writing and manual typing going forward.

What’s in the book?

Despite its size, the book is still packed with information. It contains the following chapters after the introduction:

  1. The amazing curl … 13
  2. The libcurl library … 25
  3. Your basic web page grab … 35
  4. Advanced web page grab … 49
  5. curl FTP … 63
  6. MIME form data … 83
  7. Fancy curl tricks … 97

As you can see it spends a total of 12 pages initially on explanations about curl the command line tool and some of the things you can do with it and how before it moves on to libcurl.

The book is explanatory in its style and it is sprinkled with source code examples showing how to do the various tasks with libcurl. I don’t think it is a surprise to anyone that the book focuses on HTTP transfers but it also includes sections on how to work with FTP and a little about SMTP. I think it can work well for someone who wants to get an introduction to libcurl and get into adding Internet transfers for their applications (at least if you’re into HTTP). It is not a complete guide to everything you can do, but then I doubt most users need or even want that. This book should get you going good enough to then allow you to search for the rest of the details on your own.

I think maybe the biggest piece missing in this book, and I really thing it is an omission mr Gookin should fix if he ever does a second edition: there’s virtually no mention of HTTPS or TLS at all. On the current Internet and web, a huge portion of all web pages and page loads done by browsers are done with HTTPS and while it is “just” HTTP with TLS on top, the TLS part itself is worth some special attention. Not the least because certificates and how to deal with them in a libcurl world is an area that sometimes seems hard for users to grasp.

A second thing I noticed no mention of, but I think should’ve been there: a description of curl_easy_getinfo(). It is a versatile function that provides information to users about a just performed transfer. Very useful if you ask me, and a tool in the toolbox every libcurl user should know about.

The author mentions that he was using libcurl 7.58.0 so that version or later should be fine to use to use all the code shown. Most of the code of course work in older libcurl versions as well.

Comparison to Everything curl

Everything curl is a free and open document describing everything there is to know about curl, including the project itself and curl internals, so it is a much wider scope and effort. It is however primarily provided as a web and PDF version, although you can still buy a printed edition.

Everything curl spends more space on explanations of features and discussion how to do things and isn’t as focused around source code examples as Curl Programming. Everything curl on paper is also thicker and more expensive to buy – but of course much cheaper if you’re fine with the digital version.

Where to buy?

First: decide if you need to buy it. Maybe the docs on the curl site or in Everything curl is already good enough? Then I also need to emphasize that you will not sponsor or help out the curl project itself by buying this book – it is authored and sold entirely on its own.

But if you need a quick introduction with lots of examples to get your libcurl usage going, by all means go ahead. This could be the book you need. I will not link to any online retailer or anything here. You can get it from basically anyone you like.

Mistakes or errors?

I’ve found some mistakes and ways of phrasing the explanations that I maybe wouldn’t have used, but all in all I think the author seems to have understood these things and describes functionality and features accurately and with a light and easy-going language.

Finally: I would never capitalize curl as Curl or libcurl as Libcurl, not even in a book. Just saying…

HTTP/3 Explained

I’m happy to tell that the booklet HTTP/3 Explained is now ready for the world. It is entirely free and open and is available in several different formats to fit your reading habits. (It is not available on dead trees.)

The book describes what HTTP/3 and its underlying transport protocol QUIC are, why they exist, what features they have and how they work. The book is meant to be readable and understandable for most people with a rudimentary level of network knowledge or better.

These protocols are not done yet, there aren’t even any implementation of these protocols in the main browsers yet! The book will be updated and extended along the way when things change, implementations mature and the protocols settle.

If you find bugs, mistakes, something that needs to be explained better/deeper or otherwise want to help out with the contents, file a bug!

It was just a short while ago I mentioned the decision to change the name of the protocol to HTTP/3. That triggered me to refresh my document in progress and there are now over 8,000 words there to help.

The entire HTTP/3 Explained contents are available on github.

If you haven’t caught up with HTTP/2 quite yet, don’t worry. We have you covered for that as well, with the http2 explained book.

Everything curl – work in progress

everything-curl-cover

… is a book I’m slowly working on. Click the image above to see it in its current state.  It is not complete.

As the title should hint, I intend to cover just about everything that is to say about curl. The project, the products, the development, the source code, its history, its future, the policies, the ideas and whatever else that I can think of has anything to do with curl.

The book is completely open and available for free – in a variety of formats. When I write this, there are about 60 pages and almost 13,000 words written. There are 220+ sections or sub chapters planned (so far) out of which 111 are still to be written. Of course that doesn’t really mean that the 115 already written ones are complete or without flaws that need to be corrected. I also suspect I’ve written the easiest ones first…

I welcome and encourage all the help I can get. The source is all written in markdown, and everything is on github. File issues, send pull-requests or whatever you can think of!

I’m especially interested in getting suggestions for new sections that I haven’t yet thought about. Or sub sections, or examples. Or some fun stories from the wild Internet that you overcame with the help of curl. Or suggestions on where we should insert images (and what images to insert). Or other artworks, like a nicer cover. Anything!

If things go as planned, I have filled in most of the blanks by the summer 2016 and can then offer the complete curl book.

http2 explained in markdown

http2 explainedAfter twelve  releases and over 140,000 downloads of my explanatory document “http2 explained“, I eventually did the right thing and converted the entire book over to markdown syntax and put the book up on gitbook.com.

Better output formats, now epub, MOBI, PDF and everything happens on every commit.

Better collaboration, github and regular pull requests work fine with text content instead of weird binary word processor file formats.

Easier for translators. With plain text commits to aid in tracking changes, and with the images in a separate directory etc writing and maintaining translated versions of the book should be less tedious.

I’m amazed and thrilled that we already have Chinese, Russian, French and Spanish translations and I hear news about additional languages in the pipe.

I haven’t yet decided how to do with “releases” now, as now we update everything on every push so the latest version is always available to read. Go to http://daniel.haxx.se/http2/ to find out the latest about the document and the most updated version of the document.

Thanks everyone who helps out. You’re the best!

The Mythical Man-Month

The Mythical Man-MonthFrederick Brooks wrote this classical book already back in 1975 and added a few extra chapters for the twenty years anniversary 1995…

Large portions of it feels of the age and there’s a lot of talk about Fortran, System/360 and PL-1 as if we should know about them (which made me fast forward over some chapters). But there are gems as well, and the most significant things people seem to remember Brooks’ book for are still pretty valid and fine.

Adding more people to a project leads to the need for more communication and thus it may slow down development rather than speed it up. Also known as Brooks’s law.

Given the complexity of software and software development, there’s no single method or concept that will lead to an improvement by an order of magnitude – within a decade. There’s No Silver Bullet. (This section was not in the original edition of the book.)

The risks involved when rewriting something and wants to fix everything that was wrong in the previous version so you over-work and over-design the successor. The so called Second system effect.

A lot of the book is spent on thoughts and theories around how to manage really really large software projects, like when you involve thousands of persons. Is it even possible to make such huge projects successful and if so, what does it take? The extra chapters do indeed add value since they offered Brooks a chance to re-evaluate his earlier claims and ideas and to check what seemed to be truths and what mistakes he did in the original edition.

A very interesting read that I’m glad I finally got time to get through!

80 Novels in One Go

80 romaner för dig som har brÃ¥ttomHenrik Lange is the author and illustrator of this book in Swedish that contains 80 international and some Swedish novels, each concentrated down to a single-page comic strip consisting of four squares only, and then one of them is “wasted” on the title!

They’re often really witty and yet they capture the core and culprit of the novels, and with fine illustrations to go with that!

Sagan om ringen - excerp from the book It’s a great and fun read and one of those books you can have lying around and just read a random page every now and then and enjoy them every time.

The example strip here on the right is typical for the book. A couple of thousand pages crammed into 3 squares…

Oh for the english readers, the title of the book translates to something like “80 novels for people in a hurry”. The Kindle only takes 120 more! 🙂

Dreaming in Code

Dreaming in Code coverRecently I’ve read the book Dreaming in Code by Scott Rosenberg, which primarily is a novel about the development of the open source project Chandler, but is full of diversions into related areas and side-stories about software, software projects, developments and more.

The project was initiated by Mitch Kapor who founded the Open Source Application Foundation and who’s perhaps most known for having created Lotus 1-2-3 back in 1982 and being co-founder of the Electronic Frontier Foundation in 1990.

Scott writes a lot about software development and makes numerous references to the classic The Mythical Man-Month (which I unfortunately haven’t read yet but I have it lying around at home just waiting…).

It is quite obvious that the guys never really could decide what exactly Chandler should do, and thus they spent ages arguing on the goals and the design and since they’re funded by an organization that (seemingly) doesn’t care about any profit or anything from this project, there was a whole team who could be lagging their project for ages without any real damage being done anywhere. In fact, I still don’t understand what Chandler does and what useful purpose it tries to fill!

Kapor basically spent 5 Million USD out of his own pocket money in an attempt to repeat his former favorite application called Agenda, but without knowing exactly what it should do and how. Does it sound like a solid foundation for how to make a killer app?

It is an interesting read, and after having been in the business as a consultant for more than a decade, I do recognize a lot in the book from real-life experiences. The book doesn’t exaggerate or present a worst-case scenario, it happens to follow a project that is merely a project amongst others that just… doesn’t get things done right.

Two books on China

Recently I’ve read two books (in Swedish) about China and the Chinese, and I’ll offer some quick reviews on them here.

Mei wenti!Inga problem! : om livet i dagens Kina

(ISBN: 9789127356375, Author: Lilliehöök, Catarina)

This is a 320 page story about the author’s trip to China. She studies Chinese, lives in China, travels around and eventually gets a work there. We get to follow the cultural clashes when a blond Swedish woman faces the (traditional) Chinese. It certainly is interesting and educational, but the book is a bit repetitive towards the end as the main point has already gone through by then. The book is however still a light and fast read.

Vilda svanar РTre d̦ttrar av Kina

Vilda Svanar(ISBN: 9789151845678, Author: Jung Chang, English title: Wild Swans)

This international best-seller is a 500+ page novel about three generations of Chinese women. The author’s grandma, mother and herself. Starting in the early 1900s over the years and the major changes that the poeple of China went through, all the way to modern time.

While a slightly harder read, I’d say this is much more interesting in comparison to the previous one, and it offers a great insight to why many of the cultural differences mentioned in the first book exist in the first place. It shows a people tormented by their leaders in many different ways, and a people that have learned the hard way to obey whatever they say and to stop thinking by themselves.