<|channel|>analysis<|message|>We need to explain how to create C++ builder for SEPA XML? Provide skeleton code.<|end|> <|start|>assistant<|channel|>final<|message|>Below is a **minimal, self‑contained example** that shows how you can build a “SEPA” (pain.008.001.08) XML file from scratch in C++. The goal of the program is: 1. **Create a `Document` object** with the required structure. 2. **Populate it with the data** you would normally get from your application (e.g. database, user input). 3. **Serialize** the object to an XML string or file that complies with the ISO‑20022 pain.008.001.08 schema. > **Why a C++ builder?** > In many legacy banking systems the only way to send SEPA Direct Debit messages is by producing a valid XML document that matches the official XSD. A small C++ tool lets you generate that XML at runtime without relying on heavyweight frameworks or external services. --- ## 1. Dependencies | Library | Purpose | How to install | |---------|---------|----------------| | **tinyxml2** | Simple XML DOM creation / serialization | `sudo apt-get install libtinyxml2-dev` (Ubuntu)
or use vcpkg/Conan: `vcpkg install tinyxml2` | | **fmt** (optional, for pretty‑printing) | Modern string formatting | `vcpkg install fmt` | The code below uses only TinyXML‑2 – no external XML schema validator is included. If you need XSD validation, you can add a third‑party library such as *libxml++* or *Xerces*. --- ## 2. Code Overview ```cpp // sepa_builder.cpp #include #include #include #include using namespace tinyxml2; // ----------------------------------------------------------------------------- // Helper to create an element with optional text Element* makeElement(XMLDocument& doc, const char* name, const std::string& text = "") { Element* e = doc.NewElement(name); if (!text.empty()) e->SetText(text.c_str()); return e; } // ----------------------------------------------------------------------------- // Data structures that mirror the pain.008.001.08 hierarchy struct MandateInfo { std::string mandateId; std::string dateOfSignature; // YYYY-MM-DD bool amendmentInd; // Optional amendment details – omitted for brevity }; struct DirectDebitTx { std::string endToEndId; double amount; // in EUR MandateInfo mandate; std::string debtorBIC; std::string debtorName; std::string debtorIBAN; std::string remittance; // Ustrd }; struct PaymentInfo { std::string paymentInfId; std::vector txs; double ctrlSum() const { double sum = 0.0; for (auto& t : txs) sum += t.amount; return sum; } }; struct GroupHeader { std::string msgId; std::string creationDateTime; // ISO8601 int nbOfTxs; double ctrlSum; std::string initiatorName; }; // ----------------------------------------------------------------------------- // Build the XML document from the data structures XMLDocument buildSEPA(const GroupHeader& gh, const PaymentInfo& pi) { XMLDocument doc; // XMLElement* root = doc.NewElement("Document"); root->SetAttribute("xmlns", "urn:iso:std:iso:20022:tech:xsd:pain.008.001.08"); doc.InsertFirstChild(root); // XMLElement* init = makeElement(doc, "CstmrDrctDbtInitn"); root->InsertEndChild(init); // --- Group Header ------------------------------------------------------ XMLElement* grpHdr = makeElement(doc, "GrpHdr"); init->InsertEndChild(grpHdr); grpHdr->InsertEndChild(makeElement(doc,"MsgId", gh.msgId)); grpHdr->InsertEndChild(makeElement(doc,"CreDtTm", gh.creationDateTime)); grpHdr->InsertEndChild(makeElement(doc,"NbOfTxs", std::to_string(gh.nbOfTxs))); grpHdr->InsertEndChild(makeElement(doc,"CtrlSum", std::to_string(gh.ctrlSum))); XMLElement* initPty = doc.NewElement("InitgPty"); initPty->InsertEndChild(makeElement(doc,"Nm", gh.initiatorName)); grpHdr->InsertEndChild(initPty); // --- Payment Information ----------------------------------------------- XMLElement* pmtInf = makeElement(doc, "PmtInf"); init->InsertEndChild(pmtInf); pmtInf->InsertEndChild(makeElement(doc,"PmtInfId", pi.paymentInfId)); pmtInf->InsertEndChild(makeElement(doc,"PmtMtd","DD")); pmtInf->InsertEndChild(makeElement(doc,"NbOfTxs", std::to_string(pi.txs.size()))); pmtInf->InsertEndChild(makeElement(doc,"CtrlSum", std::to_string(pi.ctrlSum()))); // Payment Type (hard‑coded for SEPA CORE FRST) XMLElement* pmtTp = doc.NewElement("PmtTpInf"); XMLElement* svcLvl = doc.NewElement("SvcLvl"); svcLvl->InsertEndChild(makeElement(doc,"Cd","SEPA")); pmtTp->InsertEndChild(svcLvl); XMLElement* lclInstrm = doc.NewElement("LclInstrm"); lclInstrm->InsertEndChild(makeElement(doc,"Cd","CORE")); pmtTp->InsertEndChild(lclInstrm); pmtTp->InsertEndChild(makeElement(doc,"SeqTp","FRST")); pmtInf->InsertEndChild(pmtTp); // Required collection date – hard‑coded for demo pmtInf->InsertEndChild(makeElement(doc,"ReqdColltnDt", "2023-12-05")); // Creditor (hard‑coded) XMLElement* cdtr = doc.NewElement("Cdtr"); cdtr->InsertEndChild(makeElement(doc,"Nm","Creditor Name")); pmtInf->InsertEndChild(cdtr); XMLElement* cdtrAcct = doc.NewElement("CdtrAcct"); XMLElement* cdtrId = doc.NewElement("Id"); cdtrId->InsertEndChild(makeElement(doc,"IBAN", "DE87200500001234567890")); cdtrAcct->InsertEndChild(cdtrId); pmtInf->InsertEndChild(cdtrAcct); // Creditor Agent XMLElement* cdtrAgt = doc.NewElement("CdtrAgt"); XMLElement* finInst = doc.NewElement("FinInstnId"); finInst->InsertEndChild(makeElement(doc,"BICFI","BANKDEFFXXX")); cdtrAgt->InsertEndChild(finInst); pmtInf->InsertEndChild(cdtrAgt); // Charge bearer pmtInf->InsertEndChild(makeElement(doc,"ChrgBr","SLEV")); // Creditor Scheme ID – hard‑coded XMLElement* cdtrSchme = doc.NewElement("CdtrSchmeId"); XMLElement* idElem = doc.NewElement("Id"); XMLElement* prvtId = doc.NewElement("PrvtId"); XMLElement* oth = doc.NewElement("Othr"); oth->InsertEndChild(makeElement(doc,"Id","DE00ZZZ00099999999")); XMLElement* schmeNm = doc.NewElement("SchmeNm"); schmeNm->InsertEndChild(makeElement(doc,"Prtry","SEPA")); oth->InsertEndChild(schmeNm); prvtId->InsertEndChild(oth); idElem->InsertEndChild(prvtId); cdtrSchme->InsertEndChild(idElem); pmtInf->InsertEndChild(cdtrSchme); // --- Direct Debit Transaction Infos ----------------------------------- for (const auto& tx : pi.txs) { XMLElement* drctDbtTxInf = doc.NewElement("DrctDbtTxInf"); pmtInf->InsertEndChild(drctDbtTxInf); // Payment ID XMLElement* pmtId = doc.NewElement("PmtId"); pmtId->InsertEndChild(makeElement(doc,"EndToEndId", tx.endToEndId)); drctDbtTxInf->InsertEndChild(pmtId); // Instructed Amount XMLElement* instAmt = makeElement(doc, "InstdAmt"); instAmt->SetAttribute("Ccy","EUR"); instAmt->SetText(tx.amount); drctDbtTxInf->InsertEndChild(instAmt); // Direct Debit Transaction XMLElement* drctTx = doc.NewElement("DrctDbtTx"); XMLElement* mndtInfo = doc.NewElement("MndtRltdInf"); mndtInfo->InsertEndChild(makeElement(doc,"MndtId", tx.mandate.mandateId)); mndtInfo->InsertEndChild(makeElement(doc,"DtOfSgntr", tx.mandate.dateOfSignature)); mndtInfo->InsertEndChild(makeElement(doc,"AmdmntInd", tx.mandate.amendmentInd ? "true" : "false")); drctTx->InsertEndChild(mndtInfo); drctDbtTxInf->InsertEndChild(drctTx); // Debtor Agent XMLElement* dbtrAgt = doc.NewElement("DbtrAgt"); XMLElement* finInstn = doc.NewElement("FinInstnId"); finInstn->InsertEndChild(makeElement(doc,"BICFI", tx.debtorBIC)); dbtrAgt->InsertEndChild(finInstn); drctDbtTxInf->InsertEndChild(dbtrAgt); // Debtor XMLElement* dbtr = doc.NewElement("Dbtr"); dbtr->InsertEndChild(makeElement(doc,"Nm", tx.debtorName)); // Optional structured postal address – omitted for brevity drctDbtTxInf->InsertEndChild(dbtr); // Debtor Account XMLElement* dbtrAcct = doc.NewElement("DbtrAcct"); XMLElement* idElem2 = doc.NewElement("Id"); idElem2->InsertEndChild(makeElement(doc,"IBAN", tx.debtorIBAN)); dbtrAcct->InsertEndChild(idElem2); drctDbtTxInf->InsertEndChild(dbtrAcct); // Ultimate Debtor – same as Debtor in this demo XMLElement* ultDbtr = doc.NewElement("UltmtDbtr"); ultDbtr->InsertEndChild(makeElement(doc,"Nm", tx.debtorName)); drctDbtTxInf->InsertEndChild(ultDbtr); // Remittance Information XMLElement* rmtInf = doc.NewElement("RmtInf"); rmtInf->InsertEndChild(makeElement(doc,"Ustrd", tx.remittance)); drctDbtTxInf->InsertEndChild(rmtInf); } return doc; } // ----------------------------------------------------------------------------- // Demo: build a SEPA file with two transactions int main() { GroupHeader gh = { "Message-ID-4711", "2023-12-01T09:30:47.000Z", 2, 6655.86, "Initiator Name" }; DirectDebitTx tx1; tx1.endToEndId = "OriginatorID1234"; tx1.amount = 6543.14; tx1.mandate.mandateId = "Mandate-Id"; tx1.mandate.dateOfSignature = "2023-12-01"; tx1.mandate.amendmentInd = true; tx1.debtorBIC = "RAIFCH22005"; tx1.debtorName = "Debtor Name"; tx1.debtorIBAN = "CH7280005000088877766"; tx1.remittance = "Unstructured Remittance Information"; DirectDebitTx tx2; tx2.endToEndId = "OriginatorID1235"; tx2.amount = 112.72; tx2.mandate.mandateId = "Other-Mandate-Id"; tx2.mandate.dateOfSignature = "2023-12-01"; tx2.mandate.amendmentInd = false; tx2.debtorBIC = "SPUEDE2UXXX"; tx2.debtorName = "Other Debtor Name"; tx2.debtorIBAN = "DE21500500001234567897"; tx2.remittance = "Unstructured Remittance Information"; PaymentInfo pi; pi.paymentInfId = "Payment-ID"; pi.txs.push_back(tx1); pi.txs.push_back(tx2); XMLDocument doc = buildSEPA(gh, pi); // Write to file XMLError eResult = doc.SaveFile("sepa_output.xml"); if (eResult != XML_SUCCESS) { std::cerr << "Error saving XML: " << eResult << '\n'; return 1; } std::cout << "SEPA XML written to sepa_output.xml\n"; return 0; } ``` ### How it works | Step | Code | Result | |------|------|--------| | **Create data** | `GroupHeader`, `PaymentInfo`, `DirectDebitTx` structs | Holds all values that will be inserted into the XML. | | **Build XML** | `buildSEPA()` | Walks through the hierarchy, creating elements and setting attributes/text. | | **Write file** | `doc.SaveFile("sepa_output.xml")` | Produces a file identical in structure to your sample (values are hard‑coded but can be replaced by runtime data). | --- ## 3. Compiling ```bash # Assuming you have tinyxml2 installed g++ -std=c++17 sepa_builder.cpp -ltinyxml2 -o sepa_builder ``` Run: ```bash ./sepa_builder ``` You should see `sepa_output.xml` in the same directory – open it to verify that it matches the structure of your sample file. --- ## 4. Extending / Customising | Feature | How to add | |---------|------------| | **Read input from CSV/DB** | Replace hard‑coded structs with a loader that reads rows and pushes them into `PaymentInfo.txs`. | | **Dynamic dates** | Use `` or a date library to format the current time. | | **Address validation** | Add optional postal address elements (`PstlAdr`) when `debtorCountry != "DE"`. | | **XSD Validation** | Link against *libxml++* or *Xerces*, load the pain.008.001.08.xsd and validate before sending. | | **Command‑line options** | Use `argparse` or `cxxopts` to let users supply file names, output paths, etc. | --- ## 5. Things to keep in mind 1. **Namespace** – The XML element names are *not* prefixed; the namespace is declared on `` with `xmlns="urn:iso:std:iso:20022:tech:xsd:pain.008.001.08"`. TinyXML‑2 does not enforce namespaces, so just keep that attribute. 2. **Formatting** – The example writes a compact XML file. If you need pretty printing, call `doc.Print()` or set `doc.SetIndent(4)` before saving. 3. **Error handling** – For production code add checks after each `InsertEndChild` to ensure the operation succeeded. --- ### TL;DR - Use TinyXML‑2 to create the XML tree. - Map your data into C++ structs, then translate those structs into XML elements. - Serialize to file or string and send it to the SEPA processing system. Feel free to copy the code above, tweak the hard‑coded values, and integrate it into your build process. Happy coding!