A tiny library to fetch relational CSV data at client-side just like JSON
Simplicity within web development is searching its way towards the client-side. With the power of Javascript, we are able to get further and further. A great example is DocumentCloud’s Backbone.js and Alex MacCaw’s Spine. Not only do they provide a lot of great features, but they are also compact (3.9kb and 2K respectively when compressed) and it’s installation (including the hosting system) is just a matter of copying the Javascript sources. So there is no need to install any server-side scripting software whatsoever.
With keeping simplicity in mind, I have created csonv.js which serves CSV data like JSON. I have chosen CSV because it’s very straightforward:
- a file represents a certain entity (equivalent to database tables)
- the CSV format is far less complex than the XML format
- CSV files consists of columns and rows which resembles attributes and records respectively
- there is no need to install extra software on the hosting server (unlike MySQL or SQLite databases)
Please note that it is also possible to nest relational data within the resulting objects as if you are joining SQL tables.
I am aware that there are a couple of cons regarding this setup. But as I am a passionate Ruby and Javascript programmer, I have build csonv.js for the sake of fun and exploring side-steps like this one! ^^
Just include csonv.js:
<script src="path/to/csonv.js" type="text/javascript"></script>
Note: include csonv.min.js for the minified csonv.js library
Make sure you have hosted the CSV files on a public location. A CSV file has to satisfy the following:
- the first row has to contain
keys– equivalent to attribute names - the second row has to describe the value
types– equivalent to data types - the following rows have to represent the
entries– equivalent to records
The data types available are:
stringor an array ofstringsintegeror an array ofintegersfloator an array offloatsbooleanor an array ofbooleans(options are: <empty>,0or1)dateor an array ofdates(RFC2822 or ISO8601)
There are two separators which csonv.js handles:
Csonv.separators.column(default:";") – Used to separate columnsCsonv.separators.array(default:",") – Used to separate array values
You can change the separators by assigning a custom one:
<script>
Csonv.separators.column = "|";
Csonv.separators.array = "/";
</script>
id;first_name;last_name;given_names;is_parent integer;string;string;strings;boolean 1;Dirk;Engel;Dirk,Julius;1 2;Anna;Engel;Anna,Octovina;1 3;Bram;Engel;Abraham,Theofilus;0 4;Paul;Engel;Paulus,Mathijs;
There are two ways to fetch CSV data as objects. Let’s say you want to fetch all the family members from (the relative path) assets/family.csv:
<script>
var members = "assets/family.csv".toObjects();
</script>
<script>
var members = Csonv.fetch("assets/family.csv");
</script>
When running JSON.stringify(members, null, 2), you will get the following JSON string:
[
{
"id": 1,
"first_name": "Dirk",
"last_name": "Engel",
"given_names": [
"Dirk",
"Julius"
],
"is_parent": true
},
{
"id": 2,
"first_name": "Anna",
"last_name": "Engel",
"given_names": [
"Anna",
"Octovina"
],
"is_parent": true
},
{
"id": 3,
"first_name": "Bram",
"last_name": "Engel",
"given_names": [
"Abraham",
"Theofilus"
],
"is_parent": false
},
{
"id": 4,
"first_name": "Paul",
"last_name": "Engel",
"given_names": [
"Paulus",
"Mathijs"
],
"is_parent": false
}
]
It is possible to fetch nested relational data with csonv.js. There are two types of relations: 1. has one and 2. has many.
Now let’s say that you have books.csv and authors.csv and you want to get all the books with their authors. Here is what you do:
The data type is specified as follows: <relative path to related CSV file>:<cardinality> of which cardinality can be either 1 or n.
For example:
id;name;favorite_book;books_read integer;string;favorites/books:1;favorites/books:n 2;Anna Engel;2;1,2,5
id;name;author integer;string;authors:1 1;To Kill an Angry Bird;1 2;The Rabbit;2 3;Parslet;3 4;The Lord of the Things;2 5;The Michelangelo Code;4
id;name integer;string 1;Harper Lee 2;JRR Tolkien 3;William Shakespeare 4;Dan Brown
The resulting books.csv data will look like this:
[
{
"id": 1,
"name": "To Kill an Angry Bird",
"author": {
"id": 1,
"name": "Harper Lee"
}
},
{
"id": 2,
"name": "The Rabbit",
"author": {
"id": 2,
"name": "JRR Tolkien"
}
},
{
"id": 3,
"name": "Parslet",
"author": {
"id": 3,
"name": "William Shakespeare"
}
},
{
"id": 4,
"name": "The Lord of the Things",
"author": {
"id": 2,
"name": "JRR Tolkien"
}
},
{
"id": 5,
"name": "The Michelangelo Code",
"author": {
"id": 4,
"name": "Dan Brown"
}
}
]
As of version 0.1.2 it is possible to fetch relational data of which the foreign keys are defined within the related association. The data type has to be specified as follows: <relative path to related CSV file>:<cardinality>:<inverse type> of which the inverse type is the inverse association that holds the foreign keys. As the foreign keys are defined elsewhere, you can leave column values blank. For instance:
id;name;author integer;string;authors:1 1;To Kill an Angry Bird;1 2;The Rabbit;2 3;Parslet;3 4;The Lord of the Things;2 5;The Michelangelo Code;4
id;name;written_books integer;string;books:n:author 1;Harper Lee; 2;JRR Tolkien; 3;William Shakespeare; 4;Dan Brown;
The resulting authors.csv data will look like this:
[
{
"id": 1,
"name": "Harper Lee",
"written_books": [
{
"id": 1,
"name": "To Kill an Angry Bird"
}
]
},
{
"id": 2,
"name": "JRR Tolkien",
"written_books": [
{
"id": 2,
"name": "The Rabbit"
},
{
"id": 4,
"name": "The Lord of the Things"
}
]
},
{
"id": 3,
"name": "William Shakespeare",
"written_books": [
{
"id": 3,
"name": "Parslet"
}
]
},
{
"id": 4,
"name": "Dan Brown",
"written_books": [
{
"id": 5,
"name": "The Michelangelo Code"
}
]
}
]
For a more complex result, please take a look at http://archan937.github.com/csonv.js for a live demo.
Well that’s about it! Doesn’t using csonv.js represent simplicity? Have fun! ^^
For support, remarks and requests please mail me at [email protected].
The String.csvSplit() function is based on Ben Nadel’s (@bennadel) blog post:
http://www.bennadel.com / his-blog-post
Copyright © 2011 Paul Engel, released under the MIT license
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