Unable to execute CURL command through java Runtime.getRuntime().exec()

Question

I am executing a curl command using java.

curl -i --user "OAMADMIN_tenant_358922247351079_svc_358922247369079_APPID:Iuj.2swilg5fhv" -H "Content-Type: application/json" -H "Accept: application/json" -H 'X-USER-IDENTITY-DOMAIN-NAME: tenant_358922247351079' -H "X-RESOURCE-IDENTITY-DOMAIN-NAME: tenant_358922247351079" --request GET "https://slc04yre-1.dev.oraclecorp.com:4443/oam/services/rest/11.1.2.0.0/oauth/admin/Clients?name=myMCS_svc_358922247369079_MCS_Client_OAUTHCLIENT"

I want to get the output of this curl command in my code,but my stdoutput is coming out to be empty.

 private static String executeCommand(String command) {
        StringBuffer output = new StringBuffer();

        Process p;
        try {
            p = Runtime.getRuntime().exec(command);

            BufferedReader reader = new BufferedReader(new InputStreamReader(
                    p.getInputStream()));
            //p.waitFor();
            String line = "";
            while ((line = reader.readLine()) != null) {
                System.out.println("line="+line);
                output.append(line + "\n");
            }

        } catch (Exception e) {
            e.printStackTrace();
        }

        return output.toString();

    }

Tried executing the curl command manually, its working fine. Then I printed the standard error, and I can see:

   [testng] error line=
   [testng] error line=curl: (6) Couldn't resolve host 'application'
   [testng] error line=
   [testng] error line=curl: (6) Couldn't resolve host 'application'
   [testng] error line=
   [testng] error line=curl: (6) Couldn't resolve host 'tenant_359516638431079''
   [testng] error line=
   [testng] error line=curl: (6) Couldn't resolve host 'tenant_359516638431079"'
   [testng] error line=
   [testng] error line=curl: (1) Unsupported protocol: "https

When curl command is executed manually, its working fine then why not through Runtime.getRuntime() ?

Kindly suggest!! Any help will be appreciated.

Answer 1

It seems like the data shell/console is interpreting/changing characters. For example the following line:

-H "Content-Type: application/json"

... seems to be getting interpreted as three different arguments:

-H Content-Type: and application and /json by the shell/console.

Try breaking the command string down into an array of components using the format:

exec(String[] cmdarray)

That way it will be clear to the shell/console which arguments are grouped together.

Here is a test in groovy that proves the point:

def Object executeCommand(command) {

   def proc = Runtime.getRuntime().exec(command);
   def sout = new StringBuffer()
   def serr = new StringBuffer()

   proc.consumeProcessOutput(sout, serr)
   proc.waitFor()

   return [ 'sout':sout.toString(), 'serr':serr.toString() ]
}   

response = executeCommand('''curl --silent --show-error -H "Accept: application/json" --request GET "https://education.cloudant.com/"''')
assert response['sout'] == ''
assert response['serr'].startsWith( 'curl: (6) Could not resolve host: application' )

response = executeCommand(['curl', '--silent',  '--show-error',  '-H', 'Accept: application/json',  '--request', 'GET', 'https://education.cloudant.com/'] as String[] )
assert response['sout'].startsWith('{"couchdb":"Welcome","version":"1.0.2","cloudant_build":"2367"}')
assert response['serr'] == ''