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Connect to live data from Harvest with the API Driver

Connect to Harvest

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Analyze Harvest Data in R


Create data visualizations and use high-performance statistical functions to analyze Harvest data in Microsoft R Open.

Access Harvest data with pure R script and standard SQL. You can use the CData ODBC Driver for Harvest and the RODBC package to work with remote Harvest data in R. By using the CData Driver, you are leveraging a driver written for industry-proven standards to access your data in the popular, open-source R language. This article shows how to use the driver to execute SQL queries to Harvest data and visualize Harvest data in R.

Install R

You can complement the driver's performance gains from multi-threading and managed code by running the multithreaded Microsoft R Open or by running R linked with the BLAS/LAPACK libraries. This article uses Microsoft R Open (MRO).

Connect to Harvest as an ODBC Data Source

Information for connecting to Harvest follows, along with different instructions for configuring a DSN in Windows and Linux environments.

Start by setting the Profile connection property to the location of the Harvest Profile on disk (e.g. C:\profiles\Harvest.apip). Next, set the ProfileSettings connection property to the connection string for Harvest (see below).

Harvest API Profile Settings

To authenticate to Harvest, you can use either Token authentication or the OAuth standard. Use Basic authentication to connect to your own data. Use OAuth to allow other users to connect to their data.

Using Token Authentication

To use Token Authentication, set the APIKey to your Harvest Personal Access Token in the ProfileSettings connection property. In addition to APIKey, set your AccountId in ProfileSettings to connect.

Using OAuth Authentication

First, register an OAuth2 application with Harvest. The application can be created from the "Developers" section of Harvest ID.

After setting the following connection properties, you are ready to connect:

  • ProfileSettings: Set your AccountId in ProfileSettings.
  • AuthScheme: Set this to OAuth.
  • OAuthClientId: Set this to the client ID that you specified in your app settings.
  • OAuthClientSecret: Set this to the client secret that you specified in your app settings.
  • CallbackURL: Set this to the Redirect URI that you specified in your app settings.
  • InitiateOAuth: Set this to GETANDREFRESH. You can use InitiateOAuth to manage how the driver obtains and refreshes the OAuthAccessToken.

When you configure the DSN, you may also want to set the Max Rows connection property. This will limit the number of rows returned, which is especially helpful for improving performance when designing reports and visualizations.

Windows

If you have not already, first specify connection properties in an ODBC DSN (data source name). This is the last step of the driver installation. You can use the Microsoft ODBC Data Source Administrator to create and configure ODBC DSNs.

Linux

If you are installing the CData ODBC Driver for Harvest in a Linux environment, the driver installation predefines a system DSN. You can modify the DSN by editing the system data sources file (/etc/odbc.ini) and defining the required connection properties.

/etc/odbc.ini

[CData API Source] Driver = CData ODBC Driver for Harvest Description = My Description Profile = C:\profiles\Harvest.apip ProfileSettings = 'APIKey = my_personal_key AccountId = _your_account_id'

For specific information on using these configuration files, please refer to the help documentation (installed and found online).

Load the RODBC Package

To use the driver, download the RODBC package. In RStudio, click Tools -> Install Packages and enter RODBC in the Packages box.

After installing the RODBC package, the following line loads the package:

library(RODBC)

Note: This article uses RODBC version 1.3-12. Using Microsoft R Open, you can test with the same version, using the checkpoint capabilities of Microsoft's MRAN repository. The checkpoint command enables you to install packages from a snapshot of the CRAN repository, hosted on the MRAN repository. The snapshot taken Jan. 1, 2016 contains version 1.3-12.

library(checkpoint) checkpoint("2016-01-01")

Connect to Harvest Data as an ODBC Data Source

You can connect to a DSN in R with the following line:

conn <- odbcConnect("CData API Source")

Schema Discovery

The driver models Harvest APIs as relational tables, views, and stored procedures. Use the following line to retrieve the list of tables:

sqlTables(conn)

Execute SQL Queries

Use the sqlQuery function to execute any SQL query supported by the Harvest API.

invoices <- sqlQuery(conn, "SELECT Id, ClientName FROM Invoices WHERE State = 'open'", believeNRows=FALSE, rows_at_time=1)

You can view the results in a data viewer window with the following command:

View(invoices)

Plot Harvest Data

You can now analyze Harvest data with any of the data visualization packages available in the CRAN repository. You can create simple bar plots with the built-in bar plot function:

par(las=2,ps=10,mar=c(5,15,4,2)) barplot(invoices$ClientName, main="Harvest Invoices", names.arg = invoices$Id, horiz=TRUE)