First, let me make your core basics clear.When you are referring to SAP ECC, you are referring to SAP ERP Central Component which is more or less equivalent to the prior SAP R3 System.  ABAP does not play any much part over here.But ABAP resides in the kernel of SAP which is referred to SAP BASIS.Speaking about your pointers for referenceHorst Keller - ABAP objects (For ABAP)Help.SAP.com  - (overall SAP)SAP ECC 6.0 Black book Then there are blogs, Q&A, and other online help always available. You can start from anywhere and when you move along, you will discover online assets as ... Read More

The answer lies within the exception message itself. The connection string that you are using to connect to the Business object server is wrongly configured. Check for each parameter, you will find something must be wrong and hence why you are receiving this error message.

You need to configure the soap manager transaction.First, specify the proxy that you have created in the configurationSpecify the portSet the access path from transport settings. The SAP is making use of ‘cl_http_client’ which has a method ‘create_by_destination’ to make an HTTP call. You can extend that to induce your logic there.

I would recommend to use LDAP_READ instead of LDAP_SEARCH and you will see thumbnail photo should be available in a convenient form to be from “XSTRING”.LDAP_SEARCH is mentioned as obsolete in SAP documentation. To see full documentation of this FM, you can use T-code SE37 to open Function Builder. Navigate to Goto ->Documentation -> Function Module Documentation.Function Module: LDAP_READ  Function Group: FSLDAP_EXTProgram Name: SAPLFSLDAP_EXTINCLUDE Name: LFSLDAP_EXTU01

The issue lies in the class you are using for making a method call. This class is basically making RFC callback with the help of SAP GUI. SO, when you are using the function builder, it works well because it has an SAP GUI connection present.But when you are using an external system, the GUI is missing and it doesn’t works. What you can try is to use some other method which does not have an RFC callback and thus will not have any problem. Try to use ‘create_with_table’ in place of your used method.

As mentioned in exception message, it seems that the function module tries to access GUI related function and it doesn’t support BAPIs. So it seems to be a custom RFC module or there is some bug in SAP coding and you should open a support ticket with SAP.Also, you shouldn’t use GUI services in non-GUI operations, and it is not suggested to use class cl_gui_frontend_services and functions GUI_* and you should use OPEN_DATASET FOR INPUT/OUTPUT instruction in RFC function.

In SAP Business One, SBO-Common is only used in functionality handling or following your company database. Normal day to day business functions happens entirely in the company database. You can create a new set of sample database SBO-COMMON by reinstalling SAP B1 server. SBO-Common database holds this information − DB List (DB's which having SAP DB Structures) DB Details like Version, Upgrade Details License Details For more details about SBO-COMMON database, you can refer below link − https://archive.sap.com/discussions/thread/1447063

Note that Image must be uploaded from system to MIME beforehand.Run Transaction SE78 → Upload (F5).You have to declare 2 variables in the interface - global data with types string and xstring, You need to change the data declaration as below −data: gv_bmp_watermark type xstring. constants: gc_url_watermark type string value '/BC/PUBLIC/MyImages/watermark100.bmp'.You need to add the following under code initialization.//* Read Images data: lr_api type ref to if_mr_api. lr_api = cl_mime_repository_api=>get_api( ). lr_api->get( exporting i_url = gc_url_watermark              importing e_content = gv_bmp_watermark).You also need to change context node a bit as mentioned below −Name: WATERMARK   ... Read More

Note that SAP.net connector doesn’t work similar to 2.0 connector. There are lot many changes- good and bad provisioned in .net 3.0 version.This is SAP documentation link about general capabilities of SAP.net connector:https://help.sap.com/saphelp_crm700_ehp02/helpdata/EN/4a/097b0543f4088ce 10000000a421937/frameset.htmSAP .NET Connector 3.0 is the current version of SAP's development environment for communication between the Microsoft .NET platform and SAP systems. With the use of SAP.net connector, you can connect SAP system to all common programming languages like: Visual Basic. NET, C#, or Managed C++ and many more. Following are the advantage of upgrading to SAP.net 3.0:This version is no longer bound to a special Visual Studio ... Read More

It does not change much in SAP. How you have been doing in other projects like .NET or other, you need to incorporate the same.You need to send a POST or GET request to the intended service with the help of URL.In order to get the URL, you need to seek help from the ABAP person who would be exposing the service to fetch the WSDL file for all the details about the service.Once you have the WSDL, you can frame the request object with all required input parameters to make an AJAX call.