A simple way to execute REST API queries, get the JSON results and populate Excel Workshseets with the result.

1. Getting REST API JSON data into
Excel
cRest primer from Excel Liberation

2. Excel Liberation for details
cRest purpose
REST APIs return all kinds of
data shapes. Getting that to a
2 dimensional Excel table can
be labor intensive
{
"Definition": "rest definition: repose, sleep; '''specifically'''.",
"DefinitionSource": "Merriam-Webster",
"Heading": "Rest",
"AbstractSource": "Wikipedia",
"Image": "",
"RelatedTopics": [
{
"Result": "<a href="http://duckduckgo.com/Rest_(music)">Rest (music)</a>, a pause
in a piece of music",
"Icon": {
"URL": "https://i.duckduckgo.com/i/1dca4003.png",
"Height": "",
"Width": ""
},
"FirstURL": "http://duckduckgo.com/Rest_(music)",
"Text": "Rest (music), a pause in a piece of music"
},
{
"Result": "<a href="http://duckduckgo.com/Leisure">Leisure</a> - Leisure, or free
time, is time spent away from business, work, and domestic chores.",
"Icon": {
"URL": "https://i.duckduckgo.com/i/753cd753.jpg",
"Height": "",
"Width": ""
},
"FirstURL": "http://duckduckgo.com/Leisure",
cRest is a VBA class that can
organize most JSON API data
an populate an Excel table

3. Excel Liberation for details
Pre-requisite classes
cRest uses two important VBA classes; cJobject (for
organizing data of variable structural depth and
converting to and from JSON) and cDataSet (for
abstracting Excel data)
You can find write ups and primer decks on Excel
Liberation.
 How to use cJobject
 How to use cDataSet
You can also find detail on cRest here.

4. Excel Liberation for details
REST API calls
These are usually made through a base API URL with
arguments to describe the query.
For example
http://api.duckduckgo.com/?format=json&q=rest
The data format is usually JSON or XML. cRest is
designed to deal with JSON. Excel has other tools
for manipulating XML

5. Excel Liberation for details
REST Excel Library
cRest is generally expecting to use a library (although you
can specify many parameters as arguments). This
simplifies re-use of APIS and also encourages the
establishment of a base of useful APIs
The library entry – (itself a cJobect) – for the duckduckgo
API looks like this
With .add("duckduckgo")
.add "restType", erSingleQuery
.add "url", "http://api.duckduckgo.com/?format=json&q="
.add "results", "relatedtopics"
.add "treeSearch", True
.add "ignore", vbNullString
End With

6. Excel Liberation for details
Setting up the output sheet
Getting data out of the JSON response and into your sheet
is a simple matter of naming the columns the same thing
as the data you want. Anything that matches gets
populated, everything else is ignored
{
"Definition": "rest definition: repose, sleep; '''specifically'''.",
"DefinitionSource": "Merriam-Webster",
"Heading": "Rest",
"AbstractSource": "Wikipedia",
"Image": "",
"RelatedTopics": [
{
"Result": "<a href="http://duckduckgo.com/Rest_(music)">Rest (music)</a>, a pause
in a piece of music",
"Icon": {
"URL": "https://i.duckduckgo.com/i/1dca4003.png",
"Height": "",
"Width": ""
},
"FirstURL": "http://duckduckgo.com/Rest_(music)",
"Text": "Rest (music), a pause in a piece of music"
},
{
"Result": "<a href="http://duckduckgo.com/Leisure">Leisure</a> - Leisure, or free
time, is time spent away from business, work, and domestic chores.",
"Icon": {
"URL": "https://i.duckduckgo.com/i/753cd753.jpg",
"Height": "",
"Width": ""
},
"FirstURL": "http://duckduckgo.com/Leisure",
Data starts at
.add "results", "relatedtopics“
We only want these 2 fields

7. Excel Liberation for details
restQuery execution
These can generally be written as a very simple one liner.
Here is a typical procedure to execute an API call and
populate the sheet. The arguments are the sheet to put
the result in, the rest library entry to use and some query
value
Public Sub testDuckDuckGo()
generalQuery("duckduckgo", "duckduckgo", _
InputBox("Enter your duckduckgo query")).tearDown
End Sub

8. Excel Liberation for details
Specifying Type of query
The duckduckgo query was this type.
.add "restType", erSingleQuery
That means that for a single query, multiple lines of data
are returned. There is another type of query
erQueryPerRow. In this case, some variable data in
each row is used as input to the query.

9. Excel Liberation for details
Query per row
In this example we want to use each value in the ‘domain
column’ and execute an API call based on it.
The library entry
With .add("page rank")
.add "restType", erRestType.erQueryPerRow
.add "url", "http://prapi.net/pr.php?f=json&url="
.add "results", ""
.add "treeSearch", False
.add "ignore", ""
End With
The caller
Public Sub testPageRank()
generalDataSetQuery("page rank", "page rank", "domain").tearDown
End Sub

10. Excel Liberation for details
More complicated column headers
Of course API data is often not two dimensional. You can
use subclass column titles as well The data
{
"total_pages": 1,
"current_page": 1,
"total_records": 73,
"records": [
{
"id": "51c857b60693b9dd1d06ce24",
"field_82": "Fashion/Wedding ",
"field_38": [
{
"id": "519a2ecd09f3ace950c70276",
"identifier": "Shopcade"
}
],
"field_39": [
{
"id": "a",
"identifier": "john doe"
},
{
"id": "b",
"identifier": "jane doe"
}
],
The column titles
Field_38.1.id
the id propertyof the first item in the Field_38 object
Field_39..identifier
all properties named identifier in the Field_39 array of objects, separated by
commas

11. Excel Liberation for details
Portability
The Google Apps Script version of cRest has the same
syntax (allowing for minor javaScript/VBA linguistic
differences)
Examples – Google Apps Script
function testDuckDuckGo() {
generalQuery("duckduckgo", "duckduckgo", _
InputBox("Enter your duckduckgo query")).tearDown();
}
There are other ways of doing this in Google Apps
Script but using cJobject in GAS allows portability to
and from VBA. It also uses Google Caching
Infrastructure is used by default so often results will
not need an API call at all.

12. Excel Liberation for details
Extensibility
Easy to extend with powerful capabilities
Examples
Get data directly from Google Fusion and populate a work sheet
getDataFromFusion "Fusion", getFusionKey(), "1pvt-tlc5z6Lek8K7vAIpXNUsOjX3qTbIsdXx9Fo“
Create queries using the Google Wire Protocol (as used by google docs)
With .add("googlecurrencyconverter")
.add "restType", erRestType.erQueryPerRow
.add "url", "http://www.google.com/ig/calculator?hl=en&q=1USD=?"
.add "results", ""
.add "treeSearch", False
.add "ignore", vbNullString
.add "wire", True
End With
Access the cJobject containing returned jSon data
for each job in crest.jobject,children
‘ do some special processing
next job
Access the cDataSet just populated
for each row in crest.dset.rows
‘ do some special processing
next row

13. Excel Liberation for details
Memory recovery
Like many objects with recursive linking, memory will not be
recovered by the VBA garbage collector simply by going out of
scope. A teardown is provided, and should be used for efficient
memory recovery.
Examples
Public Sub testFqlStream()
Dim fqlQuery As String
‘ get facebook stream data
fqlQuery = "SELECT message,share_count,likes " & _
"FROM stream WHERE CONTAINS('" & _
InputBox("message contains ?") & "')"
generalQuery("fqlStream", "fql", fqlQuery).tearDown
End Sub

14. Excel Liberation for details
Summary
These examples show some of the capabilities of
cRest Excel REST library and how to extend Excel to
use JSON REST APIs
For more detail, and to download see Excel Liberation